Iran sustained maritime forces during Afsharid dynasty that were revived in 1734 by Nader Shah, with peak of its activity lasting more than a decade until Division of the Afsharid Empire. It operated in the Caspian Sea, where it was considered a threat by the Russian Empire. Headquartered in Bushehr, the southern flotilla maintained presence in the Persian Gulf as well as the Sea of Oman, effectively pushing against maritime Arabian empires in Sultanate of Muscat and Imamate of Oman, Pirates based in coasts that were later called Trucial, and also local rebels and mutineers. Afsharid navy occasionally cooperated with the Dutch and the British.