@Tarnport @dnkboston
I've just found this about trades in middle age which is somehow amusing.
You know about Dante and you probably also know he fell in love with Beatrice Portinari (whose father was a banker).
That girl got married to Simone De' Bardi who was a member of one of the richest family in Florence. They ran a trade company with branches all over Europe, in Africa and Asia too.
We're here around 1300 (not sure the exact week ๐) but that company was probably founded some time before. This also adds to the idea that trades were quite developed in the middle age too.