From arabicnews.com: St. Catherine Monastery Mosque.
St. Catherine Monastery in South Sinai is the only monastery in the world to embrace a church and a mosque.
The mosque, of Fatimid origin, drew the attention of the German traveler Febri who visited Sinai in 1483 and the Swiss traveler Borkhart in 1816.
The later discovered patterns in the mosque that indicate that the mosque was completed in 1106.
A text was also found revealing that Emir Anoshtakin had ordered the building of the mosque during the reign of Abu Ali AI Mansur, the tenth of the Fatimid caliphs, who gave the mosque a six-step wooden pulpit.
During the Ayubid and Memluk ages, only little was known about the mosque through travelers hat visited the monastery.
The mosque, however, remained in use up till the 14th century AD, although it was neglected for a long time during the Ottoman age when it became a store- house for grains and fruits.
According to the manuscript preserved at the library of St Catherine, monks of the monastery used to confer in the mosque round 1508 AD. However, King Fuad provided the mosque with carpets and decorated the pulpits with green flags. [continue]
More on the Monastery of St. Catherine from Mirabilis.ca:
Ancient monastery opens library
At The Monastery of The Burning Bush
Ancient monastic manuscripts gain digital life