right|300px|thumb|The Livonian Confederation in 1260, showing the site for the Battle of Saule.
The Battle of Saule (; ; ) was fought on September 22, 1236 between the Livonian Brothers of the Sword and pagan Semigallians, Lithuanians and Samogitians. Some 50 to 60 knights were killed, including the Livonian Master, Volkwin; it was the earliest large-scale defeat suffered by the orders in Baltic lands. The Sword-Brothers, the first Catholic military order established in the Baltic lands, was soundly defeated and its remnants accepted incorporation into the Teutonic Order in 1237. The battle inspired Curonians, Semigallians, Selonians, Baltic tribes previously conquered by the Sword-Brothers, and Oeselians, to rebel. Some thirty years' worth of conquests on the left bank of Daugava were lost.

Background

The Sword-Brothers were established in 1202 in Riga to conquer and convert pagan Baltic tribes to Christianity. By the 1230s under the leadership of Master Volkwin, the Order was coping with strained financial resources, decreasing manpower, and ill reputation. The Order was in conflict with the papacy under Pope Gregory IX and the Holy Roman Emperor, two of its biggest supporters, over Estonia. In fall of 1236 a party of crusaders arrived from Holstein; it demanded to be led into a battle. Volkwin led a war party with the assistance of the prince of Pskov southward into pagan Samogitia. Earlier in the year the Order obtained a papal bull announcing a crusade against pagan Lithuania and Samogitia.

Events of the battle

The knights raided a group of Samogitian settlements. On the knights' northward return, however, they encountered a determined group of Samogitians at a river crossing. Unwilling to risk losing their horses in the swampland, the Holsteiners refused to fight on foot, forcing the knights to camp for the night. The next morning, on the day of Saint Maurice, the main pagan forces composed of Samogitians, likely led by Duke Vykintas, and Lithuanians, possibly led by Mindaugas arrived at the camp. The Lithuanian light cavalry flung javelins at short range, which were highly effective against the unwieldy Livonian heavy cavalry. The slaughter of these troops, including Volkwin, sowed the seeds of confusion in the Livonian ranks. The lightly-armed native forces under the command of the Brothers soon fled from the battle. Those crusaders and knights who tried to flee to Riga were allegedly killed by Semigallians.

The exact place where the battle took place is unknown. The Chronicum Livoniae by Hermann de Wartberge says the battle was fought in terram Sauleorum. This may be near Šiauliai (, ) in Lithuania or near the small town of Vecsaule near Bauska in what is today southern Latvia. Saule/Saulė means "the Sun" in both Latvian and Lithuanian languages.