Originally the territory of what is now Latgale was populated by Eastern Baltic tribes, whose language became the basis for both modern Latgalian and standard Latvian. Many Latgalians still speak the local dialect, which has a standardized written form and is therefore considered a separate language.
During the 10th�12th centuries two principalities, Jersika and Atzele, existed on the territory of modern Latgale and Eastern Vidzeme. In addition Latgalians inhabited parts of modern Pskov Oblast in Russia and Vitsebsk Voblast in Belarus.
In the first decade of the 13th century the principality of Jersika, also known as Lettia, was allied with the Principality of Polotsk and Lithuanian dukes against the Bishopric of Livonia, but was defeated in 1209. Part of it was divided between the Bishopric and the Livonian Brothers of the Sword, the remainder became a vassal country. In 1239, after the death of King Visvaldis, the latter was incorporated into the territory of the Livonian Order.
In 1242, after defeat in the Battle of the Ice, Eastern Latgale (Lotigola) temporarily passed to the Novgorod Republic. In 1263 Livonian knights started to build the Volkenberg castle near to the R?zna lake (today within the R?zna National Park).
In 1277 Grand duke Traidenis of Lithuania unsuccessfully besieged the newly built castle of Daugavpils .
In 1481�1493 Grand Prince Ivan III of Russia temporarily occupied Latgale.
During the Livonian War, Ivan IV of Russia annexed Latgale in 1577. In 1559�1562 Latgale was annexed by the Grand Duchy of Lithuania, which in 1569 was incorporated into the Polish�Lithuanian Commonwealth.
In 1621 most of the Duchy of Livonia was ceded to the Swedish Empire, but part of the Duchy including Latgale remained under Polish-Lithuanian control. This became known as the Inflanty Voivodeship. The creation of Polish Inflanty is the birth of the region we now know of as Latgale. During this period the Latgalian
