The most well-known symbol used to represent Islam is the star and crescent. However, this symbol is not Muslim in origin and was a polytheistic icon adopted during the spread of Islam. Its use today is sometimes controversial in the Muslim world, and historians say that it was the insignia of the Ottoman Empire, not of Islam as a whole. Therefore, technically, Islam has no Islamically mandated symbol. However, the word "Allah" in Arabic script or characters is widely used as a symbol of Islam in the Muslim world. It means "God" in Arabic and is used by Muslims worldwide irrespective of the language spoken. The word written in Islamic calligraphy is also used as a symbol of Islam.