Well, that depends on what you mean by 'peasant', as it's one of those words that has a different meaning in Common Knowledge versus its historical use. For this, we turn to my Medieval Armies Compilation, in particular the following answers:

• u/Rittermeister examines "What is a peasant?" in two parts;
• u/Hergrim examines the likely circumstances of an English peasant combatant in 1100;
• and also, in conjunction with u/sunagainstgold, examines the Black Prince's campaigns in 1355.

And as always, should anyone else have further material to contribute, please don't let this stop you! (Besides, the Medieval Armies Compilation is always hungry for more posts...)