In the decades leading up to the Romulan Civil War of 2276, the descendants of the former Romulan Ship-Clans secretly built a number of enormous starships, intended as a refuge for Romulans fleeing the rule of the Romulan Star Empire. They later played an essential role in winning the war. Each ship was named after the Clan that built and operated it: the Tyrava, the Kaveth and at least one other of unknown name. (TOS - Rihannsu novel: The Empty Chair)