Other powers aspiring to the Livonian Baltic access responded by partitioning the Livonian state, which triggered the lengthy Livonian War, fought between 1558 and 1583. Ivan IV of Russia took Dorpat (Tartu) and Narva in 1558, and soon the Danes and Swedes had occupied other parts of the country. To protect the integrity of their country, the Livonians now sought a union with the Polish–Lithuanian state. Gotthard Kettler, the new Grand Master, met in Vilnius (Vilna, Wilno) with Sigismund Augustus in 1561 and declared Livonia a vassal state under the Polish king. The Union of Vilnius called for secularization of the Brothers of the Sword Order and incorporation of the newly established Duchy of Livonia into the "Rzeczpospolita" ("Republic") as an autonomous entity. The Duchy of Courland and Semigallia was also created as a separate fief, to be ruled by Kettler. Sigismund II obliged himself to recover the parts of Livonia lost to Moscow and the Baltic powers, which had led to grueling wars with Russia (1558–1570 and 1577–1582) and heavy struggles also concerning the fundamental issues of control of the Baltic trade and freedom of navigation.