Sierra Entertainment /

Sierra Entertainment Inc. (formerly Sierra On-Line) was an American video-game developer and publisher founded in 1979 as On-Line Systems by Ken and Roberta Williams. Based in Fresno, California, the company was last 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. Some franchises that were published by Sierra will be published by Activision, which also announced in 2008 that it may sell the Sierra brand. Sierra Entertainment was founded in 1979 as On-Line Systems in Simi Valley, California, by Ken and Roberta Williams after the former, a programmer for IBM, bought an Apple II microcomputer with which he planned to use to develop a FORTRAN compiler for Apple computers. At the time, his wife Roberta Williams was playing text adventure games for the Apple II. Dissatisfied with the adventure games that existed at the time, she realized that modern computers could display graphics and had the potential to do more than presenting text descriptions on the