Size of an army?

While I understand that this is entirely subjective and based on the needs of a campaign, I was wondering if anyone knew what the composition of historical armies was? Modified for a fantasy environment, of course. Specifically: how many troops and types, and how were they organized?

Heroes of Battle may have the info you're looking for...

Thanks, but I'm prepping for tomorrows game and I don't have time to pick it up. Need some quck and dirty numbers.

It depends entirely on the size, wealth, climate/geography of the nation/fief/town that raised it...

Just an example, a small, rich kingdom in a mineral-rich mountainous area with a relatively low population is probably going to have a smaller army, made up of heavy infantry; i.e. guys in plate with polearms.

A large agricultural nation will tend to have large armies with a large number of light infantry (archers, light spearmen, peasants with pointed sticks, etc.), often with a heavy cavalry component.

Now, size-wise, here are some good numbers to go by for medievalesque periods...

10,000 is a fairly large for a single army that's going to be fighting another army in a field battle; usually only full nations raise armies that size, and, as such, they tend to be fairly mixed in composition; armies for city/fortress assaults/sieges tend to be that size or bigger, just to make sure the defenders can't possibly fight them off, or escape.

1000 is a good, medium-sized army for smaller kingdoms; at that scale, it's a lot more feasable for them to have largely the same type of troops (all archers, all cavalry, etc.).

100,000 is about the size of a very reasonable invasion force for taking out a medium-sized nation...it wouldn't fight another army on the field unless the enemy raised a fairly equal force to try opposing them before they split up to go after their seperate objectives.

100 is just about the fewest people you could call an 'army'...just enough to raid a village.

Oh, and I just realized you wanted organization, too...so, here are a couple of attack/defense tactics that were fairly common.

On the attack, you'll want to have your archers at the front (so they have an unobstructed shot at the enemy), and your defensive infantry (spearmen) behind them, the two types forming a line to meet the enemy. On either flank, you'd have your 'shock troops': cavalry, heavy infantry, etc., to flank the enemy once they've been engaged by your defensive line. Long story short, you pepper them with arrows, send your spearmen forward, let them engage the enemy, and then flank with your shock troops.

To counter that, you'd want to make a long, long line with your non-archer infantry, and then concentrate your heaviest, toughest, bravest troops in your center. If you have any cavalry, keep them on either flank. Your archers would be behind your battle-line, and would try to shoot at the rear of the enemy formations once they've engaged your line. Then, you try to flank while your centry tries to push through the enemy spearmen.

Now, there are all sorts of counter/counter-counter tactics and strategies and formations, but the battle-line-with-cavalry-on-the-flanks was one of the more versatile. As well, the tactics with the flanks can be endlessly modified for specific situations (i.e. mass all the cavalry on one flank so they can charge down a particular hill), but they're too numerous to go into detail.

Different medieval armies in different periods were completely different...

Anyway here's a suggestion:
1000 Knights/heavy cavalry
1000 light cavalry
2000 crossbowmen
1000 infantry with longspears
1000 infantry with axes, maces etc

In my Warcraft campaign, I'm using 10000 as a number for "big" armies. In the past Dragonlance campaign, I used 100000 for big invasion forces. In my Planescape campaign, Blood War armies can sometimes break a million (with the vast majority being semi-mindless, weak fiends), with the total number of fiends involved in the War being unknown.

By the way, what classes/levels should the soldiers be? I was thinking about Commoner-1 for a really low-quality conscript (especially in my Steampunk campaign - where muskets make these conscripts marginally effective); Warrior-1 for an avarage-quality soldier; Fighter-1 for a good quality soldier; and Fighter-2 for professional soldiers. Elite troops will be around Fighter-4; higher levels will be the equivalent of special forces, or veteran NCOs. Officers, atleast the good ones, will have several levels of Expert on them - with skills such as Knowledge (tactics) and so on.

Shades, generally that sounds about right. To be honest, everything about an army is relative to its environment. What is the technology? What is the climate? Prevailing geography? What races are represented in the army? How much fighting does the army do? What are the menaces that they face? What kind of society supports the army?

Is there a system for moving troops around the realm quickly? If there is, you will have a lean, tough force. If not, there will be many conscripts backing local heroes.

The baseline NPC IMC is Exp-1, which would be for untrained peasant levies. I use War-1 for green soldier, War-2 Trained, War-3 Experienced, War-4 Veteran, War-5 Elite. In a group 1/4 are +1 level, 1/8 +2 levels, 1/16 +3 levels, etc.