 Complete the following phrase:  Crimea: In 1556 Moscow, in alliance with Dmytro Vyshnevetsky of the Zaporozhian Cossacks attempted several raids on the Black Sea coast. This policy was abandoned after the start of the Livonian war. In 1571, while troops were away in Livonia, Crimea broke through the Oka Line and burned Moscow Russo-Crimean War 1571. This led to a strengthening of southern defenses which blocked the next raid 