of John III's campaigns, since it could be attacked by both land and sea, the campaign made use of Sweden's considerable fleet but later arguments over formal control in the long term hampered any alliance with Poland. Following la Gardie's taking of the city, and in retaliation for previous Russian massacres, 7,000 Russians were killed according to Russow's contemporary chronicle. The fall of Narva was followed by those of Ivangorod, Jama, and Koporye, leaving Sweden content with its gains in Livonia. Truces of Jam Zapolski and Plussa Subsequent negotiations led by Jesuit papal legate Antonio Possevino resulted in the 1582 Truce of Jam Zapolski between Russia and the Polish–Lithuanian Commonwealth. This was a humiliation for the Tsar, in part because he requested the truce. Under the agreement Russia would surrender all areas in Livonia it still held and the city of Dorpat (Tartu) to the Polish–Lithuanian Commonwealth, while Polotsk would remain under Commonwealth control. Any captured Swedish territory—specifically Narva—could be retained by the Russians and Velike Luki would be returned from Batory's control to Russia. Possevino made a half-hearted attempt to get John III's wishes taken into consideration, but this was vetoed by the Tsar, probably in collusion with Batory. The armistice, which fell short of a full peace arrangement, was to last ten years and was renewed twice, in 1591 and 1601. Batory failed in his attempts to pressure Sweden into relinquishing its gains in Livonia, particularly Narva. Following a decision by John, the war with Russia ended when the Tsar concluded the Truce of Plussa (Plyussa, Pljussa, Plusa) with Sweden on 10 August 1583. Russia relinquished most of Ingria, leaving Narva and Ivangorod as well under Swedish control. Originally scheduled to last three years, the Russo-Swedish truce was later extended until 1590. During the negotiations, Sweden made vast demands for Russian territory, including Novgorod. Whilst these conditions were probably only for the purposes of negotiation, they may have reflected Swedish aspirations of territory in the region. Aftermath The post-war Duchy of Courland and Semigallia south of the Düna (Daugava) river experienced a period of political stability based on the 1561 Treaty of Vilnius, later modified by the 1617 Formula regiminis and Statuta Curlandiæ, which granted indigenous nobles additional rights at the duke's expense. North of the Düna, Batory reduced the privileges Sigismund had granted the Duchy of Livonia, regarding the regained territories as the spoils of war. Riga's