Structurally the monastery's king post truss is the oldest known surviving roof truss in the world.
A mosque was created by converting an existing chapel during the Fatimid Caliphate (909–1171), which was in regular use until the era of the Mamluk Sultanate in the 13th century and is still in use today on special occasions.
In May 1844 and February 1859, Constantin von Tischendorf visited the monastery for research and discovered the Codex Sinaiticus, dating from the 4th Century, at the time the oldest almost completely preserved manuscript of the Bible.
The finding from 1859 left the monastery in the 19th century for Russia, in circumstances that had been long disputed.
In February 1892, Agnes Smith Lewis identified a palimpsest in St Catherine's library that became known as the Syriac Sinaiticus and is still in the Monastery's possession.
Agnes and her sister Margaret Dunlop Gibson returned with a team of scholars that included J.
The most important manuscripts have since been filmed or digitized, and so are accessible to scholars.
The monastery, along with several dependencies in the area, constitute the entire Church of Sinai, which is headed by an archbishop, who is also the abbot of the monastery.
The exact administrative status of the church within the Eastern Orthodox Church is ambiguous: by some, including the church itself, The archbishop is traditionally consecrated by the Greek Orthodox Patriarch of Jerusalem; in recent centuries he has usually resided in Cairo.
From the time of the First Crusade, the presence of Crusaders in the Sinai until 1270 spurred the interest of European Christians and increased the number of intrepid pilgrims who visited the monastery.
The monastery was supported by its dependencies in Egypt, Palestine, Syria, Crete, Cyprus and Constantinople.
The monastery is still surrounded by the massive fortifications that have preserved it.