Under the Romans – in their pagan form as well as after the Christianisation of their empire, for which historians use the term Byzantine Empire – Gaza experienced relative peace and its port flourished. In 635 CE, it became the first city in Palestine to be conquered by the Muslim Rashidun army and quickly developed into a center of Islamic law. However, by the time the Crusaders invaded the country starting in 1099, Gaza was in ruins. In later centuries, Gaza experienced several hardships—from Mongol raids to floods and locusts, reducing it to a village by the 16th century, when it was incorporated into the Ottoman Empire. During the first half of Ottoman rule, the Ridwan dynasty controlled Gaza and under them the city went through an age of great commerce and peace. The municipality of Gaza was established in 1893.