Previously a pagan temple and then a church, the Omari Grand Mosque in Gaza City was converted to a Muslim place of worship under Caliph Omar ibn Al-Khattab. During Roman and Greek rule, the site was a temple to worship the god Marna, said Heyam Al-Bitar, head of the tourism and archaeology department at the Tourism Ministry in Gaza. It was built during the reign of Roman Emperor Hadrian. The temple was converted to a church in 406 AD, and then into a mosque in 634 AD, said archaeologist Dr. Salim Al-Mubaid. “It was the first mosque to perform Friday prayers in Gaza after the Islamic conquest,” he added. During the Crusades, it was turned into St. John’s Cathedral in 1149 AD. It was converted back into a mosque in 1192 AD, but retained its Gothic architecture. It was expanded by Mamluk Sultan Nasser Muhammad during Ottoman rule. Large parts of the mosque were destroyed during World War I, said Al-Mubaid. Historian Othman Mustafa Al-Tabbaa said it has 38 marble columns. Al-Bitar said the mosque’s minaret, a model of Mamluk architectural style, is one of its most famous features. Its lower half is square and its upper half is octagonal. The mosque’s library, built under Mamluk Sultan Al-Zaher Baybars, was a scientific beacon for scholars. Having contained thousands of books and manuscripts on various sciences, the library was destroyed during the Crusades and World War I. Today, it contains what books and manuscripts were not destroyed or looted. It is the oldest mosque library in the Gaza Strip.