[Gregstrom]

As far as secondary skills go, I guess I have a few ideas.

In some schools of Eastern martial arts, I understand calligraphy and possibly poetry were considered as important as weapon skills. They would surely be part of any training that was undergone. Maybe religious knowledge, literacy, meditation?

Cromwell's soldiers might well have known some basics of leatherworking - enough to make leather bottles and the like - and how to make fuse cord, as well as a degree of animal husbandry and other general military skills.

A student at a German school of fencing might also be learning heraldry, court manners and dance. If the school had a military bent, maybe he'd learn maths, a foreign language or two, logistics, military strategy and the basics of codes and ciphers. Probably a bunch of other things too.

It's hard to talk in depth about the eastern martial arts, because I don't know that much about them. In the case of the formal schools, they seem to have been pretty much a student's whole life while they were in training so it seems reasonable to assume that a wide range of life skills would have been taught.

In a fantasy RPG with noticeable amounts of magic, it's probably a safe bet that any training above that of basic line infantry would cover some details of magical theory and possibly even practise.