Dark Bishop

Thanks, that's what I thought but I could not find a definite answer anywhere.

Hello all, I know this is a very noob question but I haven't been able to do a successful search of Sacred 2 forums to answer my question and I'm sure it's something simple. I've only been playing for about a day. My question is. How do you level up Combat Arts? Is it just a matter of reading more runes? What makes the green progress bar grow under each Aspect? Thanks.