Treaty of Dovydiškės

The Treaty of Dovydiškės (Lithuanian: Dovydiškių sutartis; Polish: Traktat w lasach dawidyskich or Traktat w Dawidyszkach), Daudiske, or Daudisken was a secret treaty signed on May 31, 1380 between Jogaila, the Grand Duke of Lithuania, and Winrich von Kniprode, the Grand Master of the Teutonic Knights. The treaty was directed against Jogaila's uncle Kęstutis and its effect was to precipitate the Lithuanian Civil War (1381–1384).

The treaty was signed soon after Grand Duke Algirdas' death in 1377. Algirdas named his son Jogaila as his successor and not Kęstutis, his brother and co-ruler. Kęstutis and his son Vytautas acknowledged Jogaila's title and maintained friendly relations with him even when his right of inheritance was challenged by Andrei of Polotsk, Algirdas' eldest son. The Teutonic Knights continued their crusade against pagan Lithuania. A large campaign was organized in winter of 1378. Teutons reached Brest and as far as the Pripyat River. The Livonian Order raided Upytė. Another campaign threatened the capital in Vilnius. Kęstutis offered to negotiate a truce and exchange of prisoners. On September 29, 1379, a ten-year truce was signed in Trakai. It was the last treaty that Kęstutis and Jogaila signed jointly. However, the truce protected only Christian lands in the south, thus Kęstutis' pagan realms in northern and western Lithuania were still vulnerable to Teutonic attacks. In February 1380, Jogaila, without Kęstutis, made a five-month truce with the Livonian Order to protect his Lithuanian domains and Polotsk, just taken from his rival Andrei of Polotsk.

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