I'm playing with the IGC but hopefully this is related to the game in general. I'm Russia and have discovered Isfahan, the capital of Persia (everything around it is terra incognitta), but not via exploration or maps or events. I don't recall when it appeared on the map. Is it possible to discover the capital when you enter an alliance? I believe Venice was allied with Persia and I entered the alliance - this opened up a whole new CoT for Russia.