In the north, the Livonian War took place over the strategically and economically crucial region of Livonia, the traditional territory of the Livonian Order. The Livonian Confederation formed an alliance with the Polish-Lithuanian side in 1557 with the Treaty of Pozvol. Desired by both Lithuania and Poland, Livonia was then incorporated into the Polish Crown by Sigismund II. These developments caused Ivan the Terrible of Russia to launch attacks in Livonia beginning in 1558, and later on Lithuania. The grand duchy's fortress of Polotsk fell in 1563. This was followed by a Lithuanian victory at the Battle of Ula in 1564, but not a recovery of Polotsk. Russian, Swedish and Polish-Lithuanian occupations subdivided Livonia.