Unit Experience

[Lichgod]

You do get exper for just being in a battle. Had a Principles unit that just sat out a battle (one of many he had been in) get an exper level with zero kills to his credit. So, being on site and watching the archers/cav do all the work will improve your infantry.

[Ulstan]

I have had 3 battles now where units got a level of experience, without killing a single enemy soldier or losing a single man from their unit.

[Oaty]

You do get exper for just being in a battle. Had a Principles unit that just sat out a battle (one of many he had been in) get an exper level with zero kills to his credit. So, being on site and watching the archers/cav do all the work will improve your infantry.

Same observation here. Makes sense too because experienced soldiers know the aftermath of routing