The earliest mention of the tax is found in a letter sent by Ismail (a ruler of the Nogai Horde and ancestor of the Yusupov family) to Tsar Ivan IV in 1559, three years after Ivan's conquest of the Volga Delta and Astrakhan. The border between the two polities was not yet established, and Ismail complained that Ivan's governor of Astrakhan demanded yasak from those inhabitants of the delta that Ismail considered his subjects, "in grain from those who farm and in fish from those who fish".