Sierra Online was a video game developer and publisher founded in 1980 by Ken Williams and Roberta Williams. The company is best known for creating popular adventure game series such as King's Quest, Space Quest, and Leisure Suit Larry. Sierra Online played a significant role in the development of graphic adventure games, utilizing innovative storytelling and gameplay mechanics. In the 1990s, Sierra Online expanded its portfolio to include various genres, including simulation and role-playing games. The company was acquired by Cendant Corporation in 1996 and later became part of Activision in 2004. Despite its decline in the late 1990s, Sierra Online remains a nostalgic name in gaming history.