Military Units, Part 1
Military units in Stronghold come from several places. Some of these can be built, others will produce units that can build (and man) other units for you. Most will need resources like arms, armour and gold.
From the Barracks
The barracks come in two flavours, wooden and stone ones, but both can produce the same units.
Lightweight, quick to move and with a more than fair range, these pointy-hatted chappies form your first troops. In large groups they are devastating against lightly armoured targets and with enough time can even kill the more heavily armoured knights.
Archers can also be used to fill in enemy moats, however, their lack of armour makes it necessary to have removed enemy archers from the wall first unless you are prepared to take heavy losses.
Even in later missions they will make up at least part of your forces, due to their lowly requirements. All you will need is a fletcher and enough peasants.
Another lightweight unit, the spearman's most useful when manning the walls as they are the only units capable of pushing down the enemy siegeladders, preventing your castle from being overrun by enemy troops. Spearmen are also useful to dig moats, a task in which they can be helped by archers.
In individual combat they are weak, they can make short work of archers if they manage to swarm them, however they are easy prey to any heavier armoured unit. Spearmen need to be equipped with spears, for this you will need a poleturner.
These bold (and bald) fighters are more heavily armed and armoured than the lowly spearman. Brute force is their main asset and they will relentlessly pound their maces on the heads of the enemy or his walls.
Of course these advantages come at a higher cost, as they will need both iron maces as well as padded leather jerkins.
If you push them enough and they can find no other way, they might be willing to throw sand down the enemy moat, but you'll have to keep an eye on them.
Once the enemy gets more covered up in armour, the lowly longbowmen won't be able to quickly turn the attacker into hedgehogs. Crossbowmen are your answer to this dilemma. Though they are more expensive, as they need both crossbows (at a cost of 3 wood each) and padded leather jerkins, they are vital to the defense of your castle.
The crossbowman is very fastidious and won't be bossed around into filling up moats.
The sound of the little winches will be music in your ears, unless it's the sound of the enemy crossbows being wound tight.