Courland?

I thought that European history and geography were among my fortes. The other day I was surprised to stumble on something I'd somehow never heard of: the Baltic duchy of Courland.

Located somewhere in or around Latvia, Lithuania, Estonia, and Russia, the duchy of Courland was apparently quite powerful in some earlier century.

Courland was a player in the heyday of Baltic shipping and trade. They even got in on the imperial game, and had at least two far flung colonies: some island off Africa, and the better known Trinidad & Tobago in the Caribbean.

My question to the world is: have any of you heard of Courland?