When did Gary Gygax make Dungeons and Dragons Entertainment?

Gary Gygax co-created Dungeons & Dragons (D&D) in the early 1970s, with the first edition being published in 1974. The game was developed through Gygax's collaboration with Dave Arneson and became the foundation for modern Tabletop Role-Playing Games. Gygax's work in D&D established a new genre of entertainment, blending storytelling with gameplay mechanics.