A battle between the Order of the Sword Brethren and the Lithuanians, fought as part of a campaign by the Christians of Livonia to penetrate Samogitia, the most westerly part of pagan Lithuania.
In September 1236 Volkwin, master of the Sword Brethren, led some 3,000 men, consisting of troops of the order, native auxiliaries, German crusaders, and Russian allies from Pskov, starting from Riga and moving through the frontier wilderness area into settled Lithuanian territory. After several days of plundering, the army began an orderly withdrawal (21 September), but at a site called Saule in the sources, and now generally identified as modern Siauliai (in Lithuania), its retreat was blocked by Lithuanian forces assembling from throughout Samogitia.
The attempt of the Christian army to fight its way home through difficult terrain degenerated into a rout with heavy casualties, and Master Volkwin and most of the knight brethren of the order were killed covering the retreat (22 September). The decisive defeat ended Christian attempts to gain control of the Lithuanian-held territory between Livonia and Prussia, and the loss of at least half of the military strength of the Sword Brethren hastened the incorporation of the remnants of the order by the Teutonic Knights in 1237.