Sonic the Hegehog is a franchise of video games released by Sega starring and named after its mascot character Sonic the Hedgehog. The series began in 1991 with the release of Sonic the Hedgehog on the Sega Mega Drive/Genesis, in addition to an 8-bit version of the game for the Master System and Game Gear formats. 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 Mega Drive/Genesis in North America and Europe. As of March 2007, the franchise has sold more than 45 million copies of its individual games.