The Basics:
Dungeons and Dragons, published in 1973 by TSR, was designed by Gary Gygax and Dave Arneson. Today, it is published by Wizards of the Coast, a division of Hasbro. (In 1997, TSR was bought by Wizards of the Coast. In 1999, Wizards of the Coast was bought by Hasbro.)
Why Dungeons and Dragons is Part of the Games Timeline:
Dungeons and Dragons essentially created the roleplaying game market.
Here are the other games I believe are the most culturally and historically significant games published since 1800.
More About Dungeons and Dragons:
The Dungeon Master's Guide. The Monster Manual. These books are part of the world of Dungeons and Dragons, in which people role-play as wizards, warriors, clerics, bards, illusionists, and more, trying to find treasure and improve their characters' strength.
