The Kurdish chiefdoms or principalities were several semi-independent entities which existed during the 16th to 19th centuries in a state of continuous warfare against the Ottoman Empire and Safavid Iran, at times siding with either of them. The Kurdish principalities were almost always divided and entered into rivalries against each other. The demarcation of borders between the Safavid Shah Safiuddin and the Ottoman caliph Sultan Murad IV in 1639 effectively divided Kurdistan between the two empires.