Sierra Entertainment (previously Sierra On-Line, commonly referred to as Sierra) is an American publisher founded in 1979 as On-Line Systems by Ken and Roberta Williams. Based in Oakhurst, California and later in Fresno, California, the company is owned by Activision, a subsidiary of Activision Blizzard.
Sierra is best known today for its multiple lines of seminal graphic adventure games started in the 1980s, many of which proved influential in the history of video games. The Sierra label was absorbed by its parent company in 2008. Some franchises (such as Crash Bandicoot and Spyro the Dragon) that were published by Sierra were later published by Activision.
Sierra was revived in 2014 by Activision Blizzard. It now focuses on re-releasing their old games, reviving their franchises and collaborating with independent developers for smaller projects.
Sierra Entertainment was founded in 1979 as On-Line Systems in Simi Valley, California, by Ken and Roberta Williams. Ken Williams, a programmer for IBM, bought an Apple II microcomputer which he planned to use to develop a Fortran compiler for the Apple II. At the time, his wife Roberta Williams was playing text adventure games on the Apple II. Dissatisfied with the text-only format, she realized that the graphics display capability of the Apple II could enhance the adventure gaming experience. After initial success, On-Line Systems was renamed Sierra On-Line in 1982, and the company moved to Oakhurst, California. By early 1984 InfoWorld estimated that Sierra was the world's 12th-largest microcomputer-software company, with $12.5 million in 1983 sales.