According to Russian and later Soviet ethnographer Grigory Chursin, another wave of Kurdish immigration in western parts of modern Azerbaijan may have taken place in 1589, at the time of the Ottoman–Safavid War, when "victorious Safavid soldiers" chose to stay in the conquered lands.[6] Safavids resettled Shi'a Kurds where borders of the historical regions of Karabakh and Zangezur met.[7] In the eighteenth century, many Kurdish tribes had formed tribal unions with Azeris in Karabakh lowlands.[8] Nineteenth-century Russian historian Peter Budkov mentioned that in 1728, groups of Kurds and Shahsevans engaged in semi-nomadic cattle-breeding in the Mughan plain applied for Russian citizenship.[9]