Cloak linings and arm slits

There are three things I’ve heard about cloaks in period, that my cloak plans had the possibility of violating:

1. They didn’t wear full circle cloaks in period.
2. They didn’t line cloaks in period.
3. Arm slits are 19th century.

Well, yesterday I picked up a copy of The Borgia Chronicles, because you just don’t find $20 coffee table books with that many gorgeous reproductions of period paintings all that often. Since my lord is from 15th century Aragon, this seemed potentially useful. Well, guess what I found?

The Virgin of the Catholic Kings, c. 1491

Hey look, a painting from the 1400s where the prince (front left) is wearing a cloak with arm slits, and what looks like a green lining on a blue cloak. If you don’t believe that’s a contrast lining, look at the princess’s red overgarment with white lining.

So, the full circle part of my cloak might still be wrong, but I now have an answer to anyone who tells me linings and arm slits aren’t period.