The conquest of Estonia and Latvia
Incursions by Scandinavian Vikings into the coastal areas of the Estonians and the Kuronians began in the 9th century. East Slav pressure had also appeared by the beginning of the millennium. As early as 1030 the southeastern portion of present-day Estonia was overrun, though the struggle continued for more than a century. In 1132 Estonians defeated an East Slav army, and in 1177 they attacked Pskov. East Slav incursions affected the lands of the Balts as well. The Galindians and Jotvingians were largely overrun and partially assimilated, though the latter continued to appear in East Slavic chronicles as late as the 14th century. Raiding parties are known to have occasionally penetrated into Latgalian lands as well.
The Scandinavian and East Slav incursions were accompanied by efforts to introduce Christianity among the Estonians and Balts. The earliest attempt to bring Roman Christianity to the Prussians dates from 997. The first Danish church was built in Courland about 1070, and the first Danish missionary was sent to Estonia about a century later. In 1219–20 Valdemar II, king of Denmark, conquered much of northern Estonia. By the late 12th century, Scandinavian intruders had been joined by Germans, who between 1198 and 1290 overran the remainder of what is now Estonia and Latvia. The Liv territories had succumbed by 1207. Most of Latgalia suffered the same fate a year later. Estonia was conquered by 1227 and Courland by 1263. The Semigallians held out until 1290.
The brunt of the German effort in the region was that of the Crusading Order of the Brothers of the Sword, founded in 1202 by Bishop Albert of Buxhoevden. An allied group, the Knights of the Teutonic Order, focused its attention on the lands of the Prussians, which were conquered between 1236 and 1283. The German incursions catalyzed the Lithuanian tribes, who inhabited the most-remote areas, into organizing effective resistance. The focus of struggle shifted to Samogitia, an area that separated the German holdings in Prussia from their conquests in Latvia. In 1236 the Brothers of the Sword suffered a crushing defeat at the hands of the Lithuanians and Semigallians at Saule, not far from present-day Šiauliai, Lithuania. The remnants of the Brothers of the Sword, reorganized as the Livonian Order, became a branch of the Knights of the Teutonic Order. An attempt in 1260 to overrun Samogitia likewise was defeated at Durpe (Durbe).
The old order along the Baltic coast was replaced by a number of small feudal political entities. Northern Estonia, including Revel (modern Tallinn), formed part of the Danish realm. The domains of the Teutonic Knights covered East Prussia, and those of the Livonian Order encompassed the bulk of what is now Latvia and southern Estonia. This region also included the four independent ecclesiastical states: the archbishopric of Riga and the bishoprics of Courland (Kurland; Latvian: Kurzeme), Dorpat (now Tartu, Estonia), and Ösel-Wiek. Riga itself was a free city. The German rulers subjugated the local populations but proved insufficiently strong to Germanize them. Even in East Prussia the extinction of the indigenous population took place only under considerably changed circumstances by the end of the 17th century and may have been due as much to epidemics as to cultural assimilation. Apart from the realm of the Teutonic Order in East Prussia, the German Baltic entities were internally weak. Following the pattern in feudal western Europe, internecine warfare proved endemic.