The Livonian War of 1558-1583 was one of the most important campaigns of the reign of Ivan the Terrible. Yes, and the entire XVI century, perhaps.
Livonian War: briefly about the premises
After the great Moscow Tsar managed to conquer Kazan and Astrakhan khanate, Ivan IV turned his attention to the Baltic lands and access to the Baltic Sea. Taking these territories for the Moscow kingdom would mean promising opportunities to trade in the Baltic. At the same time, the already established German merchant class and the Livonian Order were extremely disadvantageous to admit new competitors to the region. The Livonian War was supposed to be the solution to these contradictions. Briefly, we should also mention a formal reason for it. They served as a failure to pay tribute to the Livonian Order, which the Derbent bishopric was obliged to pay in favor of Moscow under the treaty of 1554. Formally, such tribute existed from the beginning of the XVI century. However, in practice, no one remembered it for a long time. Only with the aggravation of relations between the parties, Ivan the Terrible used this fact as an excuse for the Russian invasion of the Baltic.
Livonian War: briefly about the vicissitudes of the conflict
Russian troops began invading Livonia in 1558. The first stage of the clash, which lasted until 1561, ended The devastating defeat of the Livonian Order. The armies of the Moscow Tsar passed through the eastern and central Livonia with pogroms. Derpt and Riga were taken. In 1559, the parties concluded a truce for six months, which was to grow into a peace treaty on the conditions of vassalage of the Livonian Order from Russia. But the kings of Poland and Sweden hurried to help the German knights. King Sigismund II diplomatic maneuver managed to take the order under his own protectorate. And in November 1561 the conditions of the Treaty of Vilna, the Livonian Order ceases to exist. Its territory is divided between Lithuania and Poland. Now Ivan the Terrible had to confront at once three powerful rivals: the Principality of Lithuania, the Kingdoms of Poland and the Swedish. With the latter, however, the Muscovite tsar managed to quickly conclude peace for a while. In the years 1562-63 the second large-scale march to the Baltic begins. The events of the Livonian War continued to develop successfully at this stage. However, already in the middle of the 1560s, relations between Ivan the Terrible and the Boyars of the Elected Rada were becoming more acute. The situation is further worsened by the flight of one of the closest princely associates of Andrei Kurbsky to Lithuania and his transition to the side of the enemy (the cause that prompted the boyar was the growing despotism in the Moscow principality and the infringement of the ancient liberties of the boyars). After this event, Ivan the Terrible becomes more and more bitter, seeing around him as traitors. In parallel with this, there are also defeats at the front, which were explained by the prince to internal enemies. In 1569 Lithuania and Poland unite in a single state, which Strengthens their power. In the late 1560's - early 70's, Russian troops suffered a number of defeats and even lost several fortresses. Since 1579, the war for the Moscow principality has assumed a more defensive character. However, in 1579 Polotsk was captured by the enemy, in 1580 - Velikiy Luk, in 1582 the long siege of Pskov continued. It becomes obvious the need to sign peace and a respite for the state after decades of military campaigns.
Livonian War: briefly about the consequences
The war ended with the signing of extremely inconvenient for Moscow Plius and Yam-Zapolsky truces. The access to the Baltic Sea was never received. Instead, the prince received an exhausted and ruined country, which proved to be in an extremely difficult situation. The consequences of the Livonian War accelerated the internal crisis that led to the Great Troubles at the beginning of the 16th century.