What colors are found on the flags of Islamic states? What did they mean before?

Four colors prevail on the flags of modern Islamic states: green, red, black and white. In the Middle Ages, they were symbols of various religious and political parties: the banner of Muhammad and the Umayyad caliphs was green; black – for the rebels in 750 and for the Abbasid caliphs; white – among the Shiites and Fatimid caliphs (Alids) in Egypt; the red banner was first among the Kharijites (military democrats), later it was taken over by the Turks when they converted to Islam.