Star and crescent

The Islamic Crescent is a symbol consisting of a crescent with a star at the concave side. In its modern form, the star is usually shown with five points (though in earlier centuries a higher number of points was often used). The two signs together, or the crescent only, was long a symbol of Byzantium and also appeared on coins of the Sassanid Empire. Now it is often a symbol of Islam. It is seen on a number of different country flags such as Turkey, Libya, Maldives, Algeria, Azerbaijan, Malaysia, Singapore, Turkmenistan, Uzbekistan, Tunisia, Western Sahara, Comoros, North Cyprus, Mauritania, Pakistan respectively.
Flag of Ottoman Empire was the first flag featuring a crescent with a star. Other states formerly part of the Ottoman Empire also used the symbol, so the symbol emerged into popular use.