"Mega Man, known as Rock Man in Japan, is a series of games from Capcom, usually starring the character Mega Man. There are well over 50 Capcom releases bearing the Mega Man name, easily making it Capcom's most prolific franchise and is a very well-known franchise. As of December 30, 2008, the series has sold approximately 28 million copies worldwide. The Mega Man games began in 1987 with the first Mega Man game for the Nintendo Entertainment System. This was the original Mega Man series, which has since been followed by several sub-series. "
Source: Wikipedia, "Mega_Man", available under the CC-BY-SA License.