For several centuries, Russia was dependent on the powerful Mongol state — the Golden Horde. Until the mid-15th century, when it disintegrated into several Turkic-Tatar khanates. While the Tatars were engaged in internal conflicts, the centralized Russian state grew and strengthened. Once it gained strength, it engaged in a deadly struggle with them: For many years, the Kazan Khanate raided Russian lands. In 1487, the Grand Duke of Moscow, Ivan III, captured Kazan and temporarily established a protectorate over the khanate. However, it was his grandson, Tsar Ivan IV the Terrible, who finally subdued this old adversary in 1552. Immediately after Kazan, it was the turn of the Astrakhan Khanate. Its rulers sensed danger from Moscow and sought help from the Crimean Khanate and the Ottoman Empire. Despite this, in 1556, the khanate was occupied and eliminated by Russian troops. The conquest of the Siberian Khanate began at the initiative of the Stroganov merchants — the Tatars were devastating their possessions in the Urals. They financed the expedition of the Cossack army led by Ataman Yermak. In 1582, Yermak captured the Siberian capital Kashlyk (near Tobolsk). After the ataman's death, his work was continued by the tsar's voivodes, who finally subdued the khanate by the end of the 16th century. The Crimea was the most powerful of the fragments of the Golden Horde. The Tatars regularly raided Russian lands and took people into slavery, and in 1571, they even burned Moscow. The khans felt completely safe on the peninsula. Moreover, they were under the protection of the Ottoman Empire. The fate of Crimea was decided in Russia's successful wars with the Turks in the 18th century. In 1736, Russian troops first broke into the peninsula and even burned the khan's capital, Bakhchisarai. In 1774, Russia secured the khanate's independence from the Turks, and in 1783, it annexed it to its territories.