took over Teutonic Eckersberg and Johannisburg castles. Small squad of Teutonic knights which was returning from the failed military campaign against Lithuania, attacked the military camp of Kęstutis and Algirdas near the Ublik (Wobel) lake. After a skirmish Kęstutis, who was captured by the crusaders, was detained in Malbork Castle. Kęstutis, being over 60 years old at the time, was only defeated only by a third experienced knight who attacked him. Negotiations regarding Kęstutis's liberation were arranged two times but without results. The ransom, which crusaders asked for Kęstutis, was most likely too high. Kęstutis managed to escape from captivity about half a year later. He, with the help of his servant Alfas, broke a hole in a three meter-thick wall and left the castle by horses dressed up as Teutonic knights. The escape was well planned and it is assumed that Algirdas and Birutė, Kęstutis's wife, greatly contributed to the planned escape. Civil war and death Algirdas died in 1377 and left the throne to Jogaila, his eldest son from the second marriage with Uliana of Tver. Kęstutis and Vytautas continued to recognize Jogaila's authority even when his right of inheritance was challenged by Andrei of Polotsk, Algirdas' eldest son from the first marriage with Maria of Vitebsk. The Teutonic Knights continued their crusade against pagan Lithuania and both Jogaila and Kęstutis looked for opportunities to establish a truce. On September 29, 1379, a ten-year truce was signed in Trakai. It was the last treaty that Kęstutis and Jogaila signed jointly. In February 1380, Jogaila, without Kęstutis, made a five-month truce with the Livonian Order to protect his Lithuanian domains and Polotsk. On 31 May 1380, Jogaila and Grand Master Winrich von Kniprode signed the secret Treaty of Dovydiškės. Based on the terms of the accord, Jogaila agreed not to intervene during attacks by the Teutonic Knights against Kęstutis or his children. However, if providing aid to Kęstutis would be necessary to help to avoid any suspicions, it would not be a violation of the treaty. It remains controversial as motives behind the treaty are not entirely clear. Some historians blamed Uliana, mother of Jogaila, or his adviser Vaidila, while others pointed out generational differences: Kęstutis was about 80 years old and determined not to accept Christianity while Jogaila was about 30 years old and was looking for ways to convert and modernize the country. Still others suggested that