For the record, this is looking at their strength relative to the other people of their time, yes? I can only assume that given the top two on the list are powers from antiquity that this is so. (Which would make sense; the question may as well be "which military right now is greatest?" if we're not looking relative to other people of their times.)

Your list looks strong, though I should note this comes from one who cannot claim to be a military history expert.

That's one brier patch of question. I think another issue rankings wise is the context of the mission that the military was tasked with. I'd think the Israel military is a pound for pound among the greatest fighting forces, but it's not really capable of fighting an extended high level military conflict.. Conversely, there are behemoths like the Soviets and US that could end life on the planet, but weren't able to achieve success against much weaker opponents (Vietnam & Afg).

I would have the Ottomans over the Napoleon. Not only because of Civ 4 (+25% vs everything that doesn't have guns vs +1 movement?) but, the very fact the Ottomans lasted a lot longer, manage to comeback several times after getting knocked down, it's much underrated effort in the Great War, and at it's height had more territory that was better run than the French. Also instead of the Persian I would have the Japanense Army during 1890-1945.

1. Mongol Army.
2. Great Alexander's army
3. German Armies of WWs
4. Roman Military
5. Napoleon's Army
6. Arabian Army (around 800-1200 AD if I remember correctly)
7. American Military
8. Ottoman Empire
9. Athens & Sparta army (pre Alexander era)
10. Persian Empire
11. Carthaginian Army
12. Japanese Army (WWII)
13. Vietnamese Army
14. English Army (WWs)
15. Israel Army (present)
16. Russian Army (present)

I'd have Athens and Sparta a wee bit higher (And Isreal's present army) but I more or less agree with Hellalt.

1. US military
2. US miitary 1917
3. US Military every other year

I don't know about top ten, but I have to include the Christian army during the First Crusade. The reason it should be on one of the lists is not because of any tech or strategic advantage (although they way outmatched the Muslims in those categories too), but just because of the sheer numbers and the fact that armies from almost every Catholic and Orthodox nation marched under one sign, which given the age was no small accomplishment.

The Israeli military at 10? what?

Your forgetting the Prussian army. It was the greatest of the time. They had the best trained troops and were the basis for the german armies of wwi and eventually wwii. where do you think the goosestep started?

I think you should specify the English Royal Navy during its peak because their army wasn't that good. I would put Napoleon above the Germans because the Germans lost both wars, even though they were powerful. And I've never been a big fan of the Mongol army but I guess that's a matter of taste

The problem with the Mongol army is that they were an unstoppoble force that could absolutely decimate anything, ANYTHING in their path. But they never did anything to advance civilization, so they're almost forgotten.

On the other hand, the Romans are remembered for having a great military because not only did they win, lots, but they also layed the foundations for western civilization.

The Vietnamese and Japanese armies shouldn't be there I would definitely put the soviets and Royal navy ahead. And I agrewe with you SSReichsFuhrer but I think it's convenient for the purpose of a list to roll it into one

I agree with you KaiserWilly. Big deal they slaughtered people. Even though Napoleon and the Germans lost they were fighting in epic struggles against an evenly matched opponent and nearly pulled it out. (Whether they were right for doing so is another matter of course)

You kids are so cute.

1.American Military Present-day
2.Mongol army under Genghis Khan
3. England's Military in the Nelsonian period.

Beyond that, who the hell knows. Alls I know is that these 3 militaries could project power and win on a global scale, and never had to fight on their own turf.

I would be in favor of putting the first crusade army in there, because that's my favorite part of history... But I can't put any army on the list who's military was awesome for a short amount of time simply because of a bad ass leader at the helm... Because then we have to change the name of the thread to "most badass generals". Let's face it, Bohemond of Taranto was the man behind that operation. Without him, the whole thing would have failed 3 times (Once at Dorylaeum. Again when the Crusaders were sieging Acre. Again when the Crusaders were being sieged at Acre right after they got done taking the place)

you'r forgetting spaniard miliatry of xvi centuryand the beginnings of xvii century: the best of europe, (i.e. the world)

I'd question the current American military being greater than the British empire at the heights of its powers.
Currently there are multiple nations that have the capabilities to remove America from the map - the British empire was peerless.

No Checkmate. It wasn't unstopable. Let's remind you of the War of Succession. Close, but no cigar... On my list anyways.

fig, I thought we were talking about militaries, not nuclear capabilities lol. In a conventional fight (and unconventional, if the american people weren't such pussies), the american military pwnz j00.

To explain that list:

10. Israeli Military:

Well, that's ALREADY starting off with controversy, isn't it? ;) WHY do I have a military here that's existed for just around 65 years or so, hasn't conquered much, and is, depending on your point of view, possibly a malicious force?

-First, look at that list: I'm not leaving off armies just because they were nasty politically, just look further down that list and you'll see what I mean.
-This army has so often been outnumbered in the past, and just berated by som many different Arab states- and it STILL HAS STOOD
-You can go so far as to say Israel has been at war its entire existence so far, and it has STILL STOOD. THAT is a great military- you can say its been brutal, you can say they have no business being there (I'll strongly disagree, but lets not turn this into an Israel v. Arab World debate thread, plenty of those already), you can say they've gone too far (and there even I will ahve to agree to some extend, I think most of the time Israel has been justified, but lately, especially concerning recent events, even I have to say Israel's really pushing it someone needs to PEACEFULLY resolve this before a WWIII sparks WWI-style in the Middle East) but you MUST acknowledge that Israel's Army has been incredible in her existence, the sole reason she's not utterly destroyed, and I think that qualifies it for the #10 spot.

9. The Persian Army

Not much to say here... they conquered a good deal, the Immortals and cavalry were superb for the time... in Darius and Xerxes they had a couple great leaders (this ISN'T again, about the leaders so much as the militaries themselves, but a great leader DOES boost the score a bit, it IS a part of the military) and they were great- but ehy were conquered by a couple on this list, so they come in pretty low, but still respectable so far as being on the list at all, at #9.

8. The Ottoman Empire

Again, not much to say- long-lasting (from around the Renaissance to WWI) and some good points given for transitioning through not one or two but THREE periods (Renaissance, Age of Empires/18th-19th Centuries, and The Modern Era)... but as they FELL in the last of those three eras, they come in at #8 here (but hopefully #1 if you play as them on the site!) ;)

7. The Napoleonic Army

Again, we're not talking generals hee or this force would be a LOT higher, easily Top 5 and maybe Top 3, with an argument for #1 if you believe Napoleon to be the greatest military mind in history (and I think he's at least in the debate.) And, yes, this army gets bumped up a bit due to Napoleon, a great leader DOES boost the ranking. But even aside from him, this was a great military: the infantry was some of the beset of the era, the navy was good, the cavalry was great, and I'll go out there and say that not only was Napoleon's Artillery the best of the era, I'll go so far as to call it, in terms of how much artillery can mean to an army, maybe the Greatest Artillery Ever, and certainly one of if not the most influential- and when you can have a "Greatest ___ Ever" in your military (and possibly two if you wanted to throw Napoleon in there for "Greatest General" though that might be a bit too much) then you have the recipe for the #7 pick easily, this high because of the overall solid nature of the force with the amazing standouts it had, this low because it was defeated... and the force that defeated it is on this list as well...

6. The Germany Armies from 1914-1945

For obvious reasons, easily the hardest pick for me to make... and the one military on here I really can't admit to admiring in any capacity at all (at least not the Nazis, obviously, the WWI army... well, I'll get to that.) Like I said with the Israeli Army, you don't have to like an army to respect it and place it up here- and I LOATHE this one. The Israeli Army, even when they're really making me a bit angry, I can admire somewhat, for obvious reasons- not so with the Nazis, again, for obvious reasons. But you can't deny how good the German Forces through the first half of the 20th Century WERE. The Nazis had some of the most disciplined soldiers in history, so much so they WERE frightening, and characterizing them as brain-washed killing machines... is that too far? Maybe- but for a Jew like me, you'd have a hard time convincing me otherwise. They were a GREAT force, and while their Panzers aren't earning a "Greatest ___" here, as they really ARE cavalry in a sense and I think there have been better cavalry... they were the PANZERS. Scary. The army- scary. The navy- scary. The Luftwaffe- amazingly scary they were so good, easily one of the best Air Forces in the short history of that field, and somewhat amazing they did what they did even when fuel supplies were running low. Now, the WWI army- again, they just seemed to dig in and were great. The U-Boats. The Air Force. The German Armies earn their spot here because in not one but TWO wars they were essentially against so much, the Allies, the greater force... and look what they did. WWI, for a good couple years there not only were they winning, they seemed almost ready to crush England and exterminate the Jews and take over so much of the world... THAT is a true nightmare of a force, and frankly, one hopefully the world NEVER has to face again, because that WAS TOO CLOSE. WWI, they held up against so much of the world, and kept the Allies out of Germany, really held their ground... were they malicious? To be honest, I think EVERYONE involved in WWI had their Part of Shame, so the WWI-era German Army I can excuse some. They are right in the middle of this list- a POWERFUL Force... and yet lost both times. And it is thankful they did (at least Time Two, Time One, if they'd won... I don't know, honestly, if that'd have made things better, but at least it would have prevented a certain Austrian from coming to power there, in all likelihood...)

5. The Mongolian Army (Obviously of the Gengis/Kublai Khan Period)

Khan? KKKKHHHHHHHHHHAAAAAAAAAAANNNNNNNNNN!!!!!!!!!

Sorry- had too. ;) But really, that does sort of apply to the real Kahns as well. I'd say they had The Greatest Cavalry Ever, they just swooped down and DESTROYED. They conquered most of what lay before them. And... they're at #5. Why? Because a lot of the area they conquered was not really too much of a challenge, and others on this list, if put in this time period and with the weapons of this time period, could have done the same. Conquering China was difficult, and other areas, but... a lot was just a lack of enemies, whereas the othes on this list have big ones. Israel vs. About 5-7 Arab States. Persia vs. Middle East/Greece/Rome. Ottomans vs. Europe. Napleon vs. Europe and Middle East. German Armies vs. Allies. On and on. Not so too much with the Mongols. Also, after the first two Khans... not too memorable or powerful, I think. Still a great cavalry force, and the most land conquered- a fit for the #5 spot.

4. The American Military, WWII-Present

This is, obviously, maybe a bit of a biased ranking; I don't think it's biased at all to have America's Military in the Top 10, but I will concede that having it this high is maybe the Patriotism (one month until Independence Day Barbeques, Baseball, and Fireworks!) But I'd invite the naysayers to look at this force. Yes, it was an ALLIED effort that won WWII, but I'll open the doors of controversy (though I don't think that much) and say that if America doesn't fight in WWII, and doesn't join when it does, if FDR ignored England like some Americans wanted him to, then England eventually would have gone under with no help, and the world might be a VERY different, and sadder, place, with that #6 Army accomplishing its goal. So while America did NOT win WWII like so many Americans are fond of saying, it DID essentially make sure the Allies didn't lose it. And that's the European Front. The PACIFIC FRONT I'll go ahead and say was either an all-American or mostly-American victory, and a pretty great one at that, a true triumph of the American Navy in her finest hour... and that's part of what elevates the score here, to be honest, not the European front (which is a bit hard for me to say as obviously I'm biased towards that front and my Jewish grandfather fought in the American artillery there) so much as the Pacific. The American fleet being decimated and then rebounding to WIN against that force which ddestroyed it... it's not only amazing, but somehwat feel-good, and definitely so if you're an American, I think (obiwanobiwan officially apologizes for speaking on behalf of the American People again... but come on, lighten up, guys- one month until Independence Day!) After WWII, the Cold War... and (thank GOD) we never have the USA-USSR fought-out clash that was so dreaded, but the fact that America won the arms race is something (the Military-Industiral Complex Ike warned us about is killing us NOW, but that's another story.) Korea, the forgotten war (my other grandfather was a field medic or so in that war), was about a drawm so to speak, half of the nation was freed, would likely have been more if the forces didn't choose to advance like crazy. Vietnam- we lost, we shouldn't have gone, less said the better. Persian Gulf- we did that the RIGHT way, went in with friends, stayed to do just what HAD to be done, we actually had a legitimate reason, and THAT Bush realized what would happen if we stayed and left- a great job by our military, by the world's militaries that fought there to free Kuwait, and, for the record, as much as I don't approve of a lot of what his son did, I think George H.W. Bush was a decent man and a decent President, not Top 10 at all, but a decent one. Afghanistan... jury's still out, and we can only hope. Iraq- the second-coming of Vietnam, it seems, we went in, many were happy when Saddam was captured (I remember flying out of bed to come downstairs when I heard, I thought it was great and going to be this big historical moment when we left with a great victory and everything would be so much better because of what we did, and my generation would be able to say "Look what we did!" in rgards to Iraq with pride... well, I was young yet, still in middle school in 2003) and... all these years later we still are there, we wish we weren't, I think 4/5 wish we'd never have gone in at all... and yet, look at the actual MILITARY during that time. Win or lose, the MILITARY ITSELF (with the possible exception of the Vietnam forces; no slight AT ALL intended tiwards the brave men who fought and died there, but from waht I've read the men on the ground and the leaders were just not together and coherently organized on a lot of things) has been consistently one of if not the world's Best in The Modern Era. I'll go ahead and say that America has had The Best Air Force of any nation, with the RAF, Luftwaffe, and Israeli Air Force all close behind. The army has been spectacular, especially the WWII version- The Greatest Generation Indeed! The navy during this time has been magnificent, with the greatest single ship of the last 100 years- The USS Enterprise of WWII (THEY SHOULD NOT HAVE SCRAPPED HER!!! THAT makes me sad, you do NOT scrap the ship that carried your force to victory in the Pacific and did so many heroic things during those years and won more stars than anyone that the ship is simply legendary... they saved the mast/bell, but the old girl should have been preserved, the English knew better, THEY saved THEIR great ship, the HMS Victory... but I digress.) Followng the WWII-era Enterprise, more have followed, and nuclear submarines, destroyers, air craft carriers... its simply superb. The Atomic Bomb and America's nuclear arsenal I'll somewhat downplay here, as obviously that woudl literally obliterate any other force on this list- but it IS a factor in its being here. And then there are the leaders. Patton. MacArthur. EISENHOWER (if I'm not mistaken, his death was something of a WORLD mourning... now THAT is the mark of a man who really matters.) Scwartzkoff (apologies for likely grossly screwing up the spelling there.) The American Military from WWII-Present has simply had so many great things going for it, has done so many things and to such a refined degree, that it deserves its spot here at #4, in the Top 5. Why not higher? Because, to be fair, two out of the three that come before it lasted for CENTURIES and did what America has done so well for CENTURIES with their militaries, in terms of doing so much so well to such a refined degree. The other military ahead of America's never lost, and while it had a short lifespan than America's military, the fact of the matter is that it never lost no matter WHAT... and America can't say the same, and for all the GREAT leaders it has had in that time frame, America can't match the LEGEND that commands that other force. So, yes, three forces are better, Americans, we are NOT the greatest thing ever militarily. But please, we are still great, let's not get pissed- and hey, did I mention only a month until Independence Day! ;)

3. The English Empire

Yes- it goes ahead of the American Military. Sorry, but it does. They simply had TH GREATEST NAVY EVER- and I DARE anyone to prove otherwise. They're on here for all three forces, the army, navy, and air force, but let's face it- without that navy, this force doesn't crack the Top 10, because without that navy, England doesn't get to USE those other two, really, she doesn't become the power, the Empire she became. So a lot of this ranking rests on her military- and, lo and behold, it is THE BEST. I can't even think of a force to compare it to adequately, it was so overwhelmingly great at its height. The Spanish fleet petered out after getting a great head start. The Ottomans became outdated and fell to the English/Allies, so can't really rank them higher. America's Military's Navy doesn't really work, its doing amazingly, but the point is England;s did that for CENTURIES, so America, after only just short period of time, can't be ranked ahead of them. The USS Enterprise maybe equals the HMS Victory in terms of being legendary (I'd certainly rank the two equally as the two great titans of the sea... most people will KNOW what those ships are, what they did, why they're so great, even if they don't know of any other great ones) but the navy's still too young to be proclaimed better than the English Empire's. I'd argue that THIS, not Wellington, is what stopped Napoleon. If the English navy isn't the English navy, then Napoleon very well might have successfully kept on going without the English navy stopping his movements and roping him in, and maybe Napoleon even gets into England itself. Wellington stopped Napoleon on his return, when he was attempting to come BACK to power; if the navy of England didn't so harm Napoleon's efforts, maybe he doesn't need to come back at all, maybe he doesn't get kicked out. That being said, the English Army was pretty great during this period as well, one of the better armies of all-time; I don't know if I'd place it in the Top 5, but definitely in the Top 10. And then the air force, the savior in WWII. Simply a great air force, still is, and I'd say tied with Israel for being the greatest ever behind America's air force, The leaders- Wellington, Nelson, and all the rest- are superb as well. So it moves past America's Military for the #3 spot. Why not higher? The force directly ahead of it is pretty hard to vote against, and had a leader that you really can't pick against for just being a military leader... that force is the shortest-lasting on the list, but had such an impact and was so unbeatable, it simply edges past the Empire; additionally, the #1 force here is a lot like the English Empire, I think, only did a lot of what they did earlier, longer, and maybe had greater leaders. Nevertheless, the #3 spot is a pretty good ranking for England's Empire, I think.

2. Alexander's Army

I simply cannoy boot them out of this spot as hard as I try. Alexander WAS the greatest ever, I love Napoleon and others but I can't see him beating him strategically, and really- this army was GREAT. Infantry- great. Cavalry- great. Support- great. And Alexander did all of what he did with JUST the army. No navy helped him, and certainly no air force. He had what he had, and made sure that his troops were as great as they were- and they WERE. I really can't explain a further reason for this military being here- I simply cannot seem to nudge them out, the army NEVER LOST. This is about the Greatest Militaries, and this one NEVER LOST, so how do you argue against THAT? The only force ahead of it is there because it almost took the torch form Alexander's Army; different nation, but they did so much of what he did, only updated his methods, updated the weapons... and they lasted for centuries. Even still, #2 is pretty good for the briefest military on here, a Great spot for Alexander's Army.

1. The Roman Military At Its Height

This is simply the greatest, the force everyone has tried to emulate since. The BEST ARMY EVER. Alexander's Army and a couple others give chase, but NO ONE had a better, more dominating army than Rome when Rome was at its peak. The Legionaries are easily a Top 3 pick for Best Army Unit Ever; I won't say Best because maybe Alexander's Hoplites desrve that for never losing, but the Legionaries are damn near close. What's more, Roman Legionaries DEFEATED Greek Hoplites when the two met- they weren't ALEXANDER'S HOPLITES, so I can't say that the Roman Legionaries might have defeat THEM, they were so well trained by Alexander I honestly can't picture them ever losing. But Rome's Legionaries were incredible, they could defeat any organized army they met (I say organized because they DID lose to guerilla fighters like those in Germany and sometimes in England, but that can be said of many forces on this list, because of the natural advantage guerillas have in that sort of a situation, so I really don't hold it against the Legionaries.) What elevates the Amry to the Best Ever, however, isn't merely the Legionaries, if it were just them, as said, Alexander's Hoplites would trum them and HE would be #1. But Rome was a SMART conquerer, and allowed for some freedom in the states they took over- as such, many more of their conquered subjects responded better, and certainly better over time, and so Rome had an influx of units from all around the Ancient World. From Africa, from Greece, from the Middle East, from Europe- they had so many smaller divisions of diverse units, they could win wherever they went, because they had the APPROPRIATE TROOPS for wherever they went. The Middle East- they'd have some mercenary cavalry that rode better in the terrian to support their own, and maybe some light infrantry/slingers/bowmen from the area to support eh Legionaries. And the same principle worked all around. The Army simply dominated, and the only thing that eventually stopped them WAS a guerilla force, in Germany, NOT an organized force; the guerillas at Tuetenberg Forest stopped Rome cold, and THERE was where the line was drawn. If not for them, Rome might have kept going, and THERE is an interesting situation in itself- how far, what might have happened to the Germanic languages, and as Germanic barbarians eventually WERE the forces that conquered Rome, what might have happened if their predecessors had been eliminated early, when the Romean Army was powerful? The languages would likely have been preserved, as much was assimilated into Roman culture. The Roamn Army that lost and was destroyed eventually was a FAR weaker one than the Army of Teutenberg Forest; THAT was an army not too far removed from the Caesar days, whereas the one that saw the end of the Empire was one made up of far more mercenaries, poorer trained soldiers, and was itself a couple centuries removed from the glory days of Rome. If they had won in the Forest, had kept going, could they have taken Germany, and from there, were? The Steppes? Could Rome have mingled in the Asian continent? Likely not, that would likely have been too far even for Rome- but its still something to think about, and not many forces are so great as to allow for such thought. With most o the above forces, you can see them losing; except for Alexander's, all did or have in the past. With Rome at its Height, even when they LOSE you somehow can't see their loss as their Waterloo or the point where they cease being a threat. Rome's navy is often overlooked, and mainly served to support the soldiers, but was great as well. The leaders, from Caesar to Pompey to many of the emperors who gained power that way, were great. In fact, thare is something telling about the fact that during that time period, the only organized army that could frequently beat a Roman army was another Roman army. The mystique of the Roman amry is unmatched by any other nation. It has inlfluenced all others that have come after it. Any great army, peaceful or not, stands compared to Rome's. The conquerors that have come after have been compared to Alexander and Caesar, Alexander for his sheer military genius and Caesar, too, for that genius... and yet the Caesar comparison lends more to the Roman Army. If your army is to be declared great, it must be measured against Rome's. If you are going to have a nation, like the English Empire or what the Nazis attempted or what America is doing currently, that acts as a sort of World Power to such a degree that they nearly become, for better or worse (and though there are circumstances where it can and has been the former, most of the time it is, in the end, for the worse) World Police, they must be compared to the Romans. Rome is like, ironically enough as they professed PEACE, The Beatles in that regard- they wren't, either of them, the first to be great in their field, being a Great Army or Great Band, but they are The Greatest, and now if you are to stake a claim to that or want to be thought of as one of the greatest, you MUST compare yourself to John, Paul, George, and Ringo, and MUST compare yourself to the Roman Army from the time of Hannibal's defeat to about 150 AD.

And that's the list, folks. Peace- and one month until Independence Day! ;)

Roman military didn't project power on a global scale. Alexander's army was only bad ass because of Alexander. English Empire actually deserves to be on the list. The American military of WW2 was laughable. Oh, look... Mongols deserve to be there. German armies got overwhelmed, sorry. Napoleonic army was only bad ass because of it's leader. It's navy sucked which drug down the overall quality of it's "military" to where it can't be on the list. Ottoman Empire had no global reach. Persia got it's ass handed to it by a handful of pantywaste greeks. Israel's military sucks compared to the US military.

There you have it. Your list blows.

smatter of fact the real honor americans deserve in the ww2 is to have exploded a pair of nuclear bumbs over japan (otherwise i'm not so sure they'd have won the pacific war) and to keep germany diverted in the west while russia, the real winners, totally destroyed germany in the last russian unstopable advance

@amon
succesion war was xviii cenury, (read my comment again)

http://www.youtube.com/watch?v=1ENxbnMiqHc

Found that funny... watch the part with the Germans ;)

And I'm just not going to dignify all this America-sucked-in-WWII talk... for once, I'm just NOT getting into it...

@Checkmate- You've got that big ol' fleet battle between the Spanish armada and the English navy to worry about in the Spanish deal (1588). The Spanish weren't the premier military, but they were too prestigeous of a country (and wealthy) to fight against. Though it did project power on a global scale, it doesn't meet the requirements of being one of "the best" in the world, because it had rivals. The militaries on my list have no serious rivals at their time at all. Everywhere they went they conquered mess, lost no serious battles, and weren't dependent upon grand leaders.

i'm not saying it was "the best", i jus said you was forgetting it

Pre-gunpowder: Roman Army tops because of their level of training, discipline, organization, logistics, and advanced medical support was not seen till modern armies. Every legion had their own engineers, doctors, and craftsman. The legion was a true killing machine, some historians estimate more people where killed by the gladius than any other weapon till the musket. Assyrian Army (organization, training, etc best till Rome), New Kingdom Egyptian Army(The light chariot was the first true blitz weapon), Qin Dynasty Army(innovative arming made it unmatched in the east), Persian Army(the first multinational army), Parthian Army(first true cav army in the west), Mongal Army(mobile warfare unmatched till the tank). Macedonian Army(good combined arms army), round out pre-gunpowder armies.

Is it just my gaping knowledge of the century, or were there no great fighting forces during the 1600's? (Aside from possibly the turks)

i have mentioned them kaiser

To be honest, I have never seen the Spanish Military as particularly powerful. While they were able to conquer large pieces of land in their golden age, the people they were fighting weren't very strong (Naples, Sicily, Netherlands, Turks). Spain was never able to take on a real power (e.g. France) and win. Even at Lepanto, Spain had lots of help from other nations.

Anyone who doesn't put the Mongols at the top of the list is a maroon.

My list:
1) Mongols (no explanation needed) (and just to correct those who think the Mongols contributed nothing to humanity - they did in fact create an enormous free trade zone which allowed the dissemination of goods and ideas around most of the Eurasian landmass to an extent that had never been possible before. Columbus' voyages wouldn't've been possible without technology that originated in China and spread west through the Mongol Empire)
2) The Arabs (ca. 632-720 - these people conquered one of the world's two greatest superpowers at the time in one fell swoop and came close to conquering the other. Mongols aside, I challenge you to find an example of such a nation achieving more from such humble beginnings)
3) Alexandrine Greeks (kicked everyone's butt and kept on kicking, even after Alexander died)
4) British Empire (1700s-1920s - on the list for its virtually unchallenged naval supremacy and for no other reason.
5) Vikings. They kicked butt all over Northern Europe (and then some) for hundreds of years and no one could stop them. Also discovered some big continent or something.

The Romans are not on my list because they were defeated too many times and were consistently slaughtered by their arch-nemesis (the Parthians and later the Sassanids of Persia) - Rome was a cultural and economic power first, and a military power second (or third).

As for the First Crusade, 1) Bohemond of Taranto was not the leader (he was also seriously defeated twice; the first resulted in his capture and imprisonment for three years) and 2) the only reason it was successful was because the various Muslim states were too busy fighting each other to take notice of the (mostly) ill-equipped and untrained rabble marching through their lands (until it was too late).

Y'all are looking at 'Spain' the wrong way. 'Spain' didn't exist in the 16th century. It was still a collection of independent kingdoms that just happened to be ruled by the same person. That same person also just happened to have substantial holdings in modern Benelux, Germany, and Italy. It would be much much more accurate to talk about the "Hapsburg Empire", which was indeed quite a badass in the 16th century; without it the Turks probably would've conquered a lot more than it did. It also (or rather, some of its subjects who were loyal to it to varying degrees) conquered the two great empires of the Americas with just a handful of men - one of the most impressive feats in world history.