AGIWiki/Sierra

Sierra, or Sierra-Online, is the gaming company behind the original AGI based games. It was founded in 1980, by Ken & Roberta Williams after their success with one of the first graphical adventures made, called Mystery House.

Sierra went on to create several AGI and SCI games based out of their Oakhurst, California headquarters.

Between 1996 and 1999, several corporate shakeups involved Ken Williams leaving Sierra, and the closure of several departments of the company, including the Oakhurst Studio(Yosemite Entertainment), where adventure games were produced.