The Great Temple on Sarrassia was built by the Grumani Hierophants some time following the Great Hyperspace War. It was an underground structure which was located beneath Mount Diligence and separated by an underground lake. While it was official built to honor the religion's deities, the Great Temple's true purpose was to safeguard the Helm of Ieldis, a powerful Sith artifact created by the Sith Lord Ieldis. Around 1039 BBY, the Helm of Ieldis was moved by the archaeologist Mercia Holt and her husband Aron Holt to Skarpos in an attempt to hide it from the Sith Lord Odion.
In 1032 BBY, the Great Temple was destroyed during the Invasion of Sarrassia when priestess Zoojoo activated a remote detonate bomb that obliterated the temple, burying it beneath tons of rock and killing herself in the process.