After the Livonian War (1558–1583), Livonia (Northern Latvia & Southern Estonia) fell under Polish and Lithuanian rule. The southern part of Estonia and the northern part of Latvia were ceded to the Grand Duchy of Lithuania and formed into the Duchy of Livonia (''Ducatus Livoniae Ultradunensis''). Gotthard Kettler, the last Master of the Order of Livonia, formed the Duchy of Courland and Semigallia. Though the duchy was a vassal state to Lithuanian Grand Duchy and later of Polish and Lithuanian commonwealth, it retained a considerable degree of autonomy and experienced a golden age in the 16th century. Latgalia, the easternmost region of Latvia, became a part of the Inflanty Voivodeship of the Polish-Lithuanian Commonwealth.