Bethesda Softworks LLC is an American video game publisher based in Rockville, Maryland. The company was founded by Christopher Weaver in 1986 as a division of Media Technology Limited. In 1999, it became a subsidiary of ZeniMax Media. In its first 15 years, it was a video game developer and self-published its titles. In 2001, Bethesda spun off its in-house development team into Bethesda Game Studios, leaving Bethesda Softworks to focus on publishing operations.

Reference: Wikipedia