Originally founded by the Emperor St. Justinian the Great in 527, the monastery has weathered numerous changes in the history of the region, including the invasion of Islam, whose founder Mohammed himself guaranteed protection for the monastery. (The monastery still has possession of a written document from Mohammed to prove it.) A number of ancient icons are also on the grounds, including the famous Pantokrator of Sinai (7th c.), pictured at left, and The Ladder of Divine Ascent (12th c.), an iconic representation of the book by that name by St. John Climacus.