Gary Gygax, who co-created the Dungeons & Dragons fantasy game, died Tuesday in his home at Lake Geneva. He was 69. He helped start the role-playing phenomenon in gaming world.

He had been suffering from health problems for several years, including an abdominal aneurysm, said his wife, Gail Gygax.

Gygax create Dungeons & Dragons in 1974 with Dave Anderson using medieval characters and mythical creatures. The game became famous and well known for its oddly shaped dice. It was popular particularly among teenage boys, and eventually was turned into video games, books and movies.

His full name was Ernest Gary Gygax and his father was a Swiss immigrant who played violin in the Chicago Symphony Orchestra, read fantasy books to his only son and hooked him on the genre.

Gygax dropped out of high school early. However he did take some classes like anthropology at the University of Chicago. He was working as an insurance underwriter in the 1960s, when he began playing war-themed board games. And that’s where his successful career began.