Curonia (mod. Kurzeme, Latvia; Ger. Kurland) was a province of medieval Livonia covering roughly the peninsula between the Baltic Sea and Gulf of Riga. It was inhabited at the inception of the Baltic Crusades by the Baltic tribe of the Curonians (Kurs) and the Finno-Ugrian Livs.
According to the chronicler Henry of Livonia, the Curo- nians made peace with the emerging bishopric of Riga in 1201. In 1210 they besieged Riga, but there are indications that peace was restored and that it was even possible to use the land route to Prussia via Curonia. The Christianization of Curonia was first pursued seriously during the activity of the papal representative Baldwin of Aulne, who in 12301231 agreed with the Curonians on the acceptance of Christianity and subjected the land directly to himself and the pope. Yet it was impossible for Baldwin to enforce this settlement because it ignored the ambitions of other parties among the Germans in Livonia. Following attempts to establish a bishopric and division of the land with the Order of the Sword Brethren, a new settlement took shape in 1245, when the papal legate William of Modena granted two-thirds of the land to the Teutonic Order, and the remaining third to the bishop of Curonia, after the model of a similar settlement in Prussia. However, the province remained in a turbulent situation, experiencing a major Curonian uprising in 1260 after the Teutonic Order was defeated at the battle of Durben. A final peace agreement was reached only in 1267. Some chieftains of the Curonians were able to keep their position as fief-holders of the order.
The most important stronghold of the Teutonic Order in Curonia was Goldingen (mod. Kuldīga, Latvia). Another important castle was Memel (Klaipeda, Lithuania), founded jointly by the Livonian branch of the order and the bishop of Curonia in 1252 as the seat of the bishopric, which, however, was moved later to Pilten (mod. Piltene, Latvia). From 1326 the castle of Memel and its commandery belonged to the Prussian branch of the Teutonic Order. In 1263 a priest of the order, Emund von Werd, was elected as bishop of Curonia. During his episcopate, it was ordained that the members of the cathedral chapter should be elected from the Teutonic Order, which effectively placed the bishopric under the order’s control.
In 1561 Curonia was converted into a hereditary duchy by the last master of the Teutonic Order in Livonia, Gotthard Kettler. Although he had aimed to become ruler of all of Livonia by the secularization of all the order’s lands and an oath of allegiance to Poland, he was left only with the districts south of the river Düna.