SheepShaver is an open source PowerPC Macintosh emulator, allowing users to run Mac OS 7.5.2 through 9.0.4 on modern systems. It serves as a replacement for the Classic Environment no longer supported by recent Mac OS X versions. Setup guides are available for Windows, Mac OS X, and Linux builds, and a supportive forum is hosted on the site. SheepShaver originated in 1998 as a commercial MacOS emulator, eventually becoming open source in 2002. Development was led by Gwenole Beauchesne, with contributions from volunteers since his departure in 2008. The emulator’s name pays homage to ShapeShifter, a Mac II emulator for AmigaOS.
https://www.emaculation.com/doku.php/sheepshaver