Sonic the Hedgehog is a franchise of video games released by Sega starring and named after its mascot character. The series began in 1991 with the release of Sonic the Hedgehog on the Sega Mega Drive/Genesis, Master System and Game Gear. Sonic was responsible for turning Sega into a leading video game company during the 16-bit era, and his first game soon replaced Altered Beast as the default pack-in game for the Genesis. As of 2008, the franchise has sold more than 50 million copies.