Peasants were forcibly conscripted and fought along with mercenaries and a small amount of professional household warriors.

>>385607
>lord goes to his village
>hey come fight in this war for me or I'm going to tax the fuck out of you
>okay

>>385619
I should also note that in many cases, conscripts weren't always just awfully trained rabble given a shoddy little spear and used as arrow fodder. Middle and upper class conscripts had pretty good equipment and tended to fight better as well. The Roman Republic is a good example of this.

>"Those guys are dicks. Let's go kill them, take their stuff, and use the survivors to work the mines instead of us so we can make more weapons".
Why not go to war?

Have you ever played mount and blade?

>>385607
The household and immediate garrison gear up and messengers fan out with orders to muster at a certain time in a certain place.

The recipients of those orders raise their own households and garrisons (or don't) and send out messengers to their own subordinates.

Besides the regulated number of specifically equipped and trained soldiers expected of each officer, there are volunteers, mercenaries, and levies.

>>385607
Depends on the government really. Feudal systems had a central king who told his Barons and Dukes it was time to mobilize, and it was the job of the Lords to scrounge up men for war. The Roman Republic originally had landowners fight. Most tribal societies had warrior classes or deemed a certain age to be the "fighting age" and at that point you were just expected to be part of the army.

It was conscription in most cases though.

The Burgomeisters of Germany during whatever-the-fuck era, I don't remember right now, conscripted infantry and then expected then to pay for their own weapons and gear out-of-pocket

The main answers are here already. There are some interesting things in the details.

For instance, modern industrialized nations typically tout the value of all-volunteer militaries and keep conscription in their back pocket for emergencies always. However, mass conscription can be very effective when used liberally and unflinchingly.

The French "Levée en masse" system was a revolution (if you'll pardon the pun) that allowed post-revolutionary France to resist simultaneous attacks from most of it's neighbors, and then go on to overrun most of Europe in the following decades. To paraphrase Napoleon, "I lose 20,000 men a month. You cannot defeat me."

What he meant by that was that the many other European militaries of the age had become built around relatively small, professional armies augmented by mercenaries that while often very effective lacked a major system for replacements in the event of serious defeats. The French organized a system whereby they could lay hands on able-bodied men of all ages and put them into the army as needed. Even if they were qualitatively inferior, they were quantitatively superior and could overwhelm their foes, even coalitions of multiple foes. As Stalin famously said, "Quantity has a quality all its own."

So that's an example of wholesale conscription and a willingness to send a sizable portion of one's male population off to die will allow you to outdo model armies of professionals, no matter how good they are.

Read of up on Levée en masse to learn a bit about the methods involved in mobilizing your population in this way.

>>385699

Pre-Marian Rome was the same. Citizens meeting the property requirements to be eligible for military service were also generally obliged to equip themselves. A nice two-fold bonus; property owners had a stake in the defense of their lands, and also had the means to arm themselves.