Jelgava (; , ; see also other names) is a state city in central Latvia about southwest of Riga with 55,972 inhabitants (2019). It is the largest town in the region of Zemgale (Semigalia). Jelgava was the capital of the united Duchy of Courland and Semigallia (1578–1795) and the administrative center of the Courland Governorate (1795–1918). Jelgava is situated on a fertile plain rising only above mean sea level on the right bank of the river Lielupe. At high water the plain and sometimes the town as well can be flooded. It is a railway center and is also host to Jelgava Air Base. Its importance as a railway centre can be seen by the fact that it lies at the junction of over 6 railway lines connecting Riga to Lithuania, eastern and western Latvia, and Lithuania to the Baltic sea. Name Until 1917, the city was officially referred to as Mitau. The name Jelgava is believed to be derived from the Livonian word jālgab, meaning "town on the river." The origin of the German name Mitau is unclear, although it is suggested that it came from the Latvian words mīt or mainīt, meaning "to exchange" or "to trade," thus making it "trading-place." An alternate explanation is that Mitau came from Mitte in der Aue, German for "the middle of the Aa", referring to the Lielupe River, formerly known as the Courland Aa (Kurländische Aa in German). In Yiddish, the city was known as מיטאַווע (Mitave) or מיטאַו (Mitar). In publications dating from the Soviet period, the city name was occasionally spelled in English as "Yelgava", a back-transliteration from Russian Елгава. History The Livonian settlement began developing in the Mitau locality between the rivers Lielupe and Driksa during the 10th century. Led by the Grand Master , the crusading Livonian Order constructed the castle in Mitau on a natural island fortification (Pilssala) in 1265–1266. Using Mitau as a southern fortress, the German knights subdued the surrounding Livonians and Semigallians by 1290. The town rose in importance as a defensive fixture against the Lithuanians to the south, who succeeded in plundering Mitau in 1345. As a result of the fall of the Livonian Order in the Livonian War of 1558-1583, Mitau became a town of the Duchy of Courland in 1561. Mitau received city rights in 1573, and became the capital of the united duchies of Courland and Semigallia in 1578.