In the 2220s, the Imperial government forcibly relocated Kaveth Ship-Clan from Remus' south-tropical continent to Mirhassa and Ssuvat, among other worlds, to isolate them from other political dissidents. The Kavethssu smuggled out a number of plants from their homeworld, including the plant from which tivish fabric was produced, and began smuggling it back to Romulus and Remus. (TOS novel: The Empty Chair)
Following the the Hobus supernova in 2387 and the subsequent Romulan Civil War, Mirhassa had the only remaining shipyard in the Star Empire capable of constructing and servicing the Grand Fleet's largest warbirds. In 2410, one week into the Iconian War, a Herald-Elachi fleet attacked Mirhassa, destroying the orbital forts before they could bring their deflector shields online. The Heralds then glassed twenty major cities while the Elachi began kidnapping survivors, including the daughter and heir of Commander Revarek tr'Kaveth, planetary governor and chieftain-designate of the Ship-Clan. The attack was interrupted and foiled by a Klingon fleet led by General Ja'rod, son of Torg.