The Tantive IV was a CR90 corvette in the service of the Royal House of Alderaan. The ship was a central player in the events following the end of the Clone Wars and the beginning of the Galactic Civil War.
It started life as a CR90 corvette named Star of Alderaan, but was renamed in honor of diplomats from Tantive IV who visited Alderaan. The ship sported twin turbolaser turrets and a massive drive block of eleven ion turbine engines.
Looking for more info about the ship? Check out this wiki article