he castle surrounded by a picturesque scenery is located in the territory of Bauska town, on the land strip between the rivers Mūsa and Mēmele, not far from the place where the rivers meet to form the river Lielupe. The Bauska castle complex consists of two parts. The oldest of them – Livonia Order Castle – was built in the middle of the 15th century, but only ruins have remained up to nowadays. While the newest – residence for the Duke of Kurzeme (Courland) – was built at the end of the 16th century.
The Bauska Castle was built during the rule of the Master of the Livonian Order, Heidenreich Vinke von Overberg (1439 – 1450). The Livonian Order constructed the castle to strengthen their power over Semigallia, protect the border with Lithuania and control the trade route from Lithuania to Riga. The Bauska Castle was not only a fortification, but also the centre of the vogtei (the Order's district) where the vogt as an official fulfilled his court, police, financial and war administration responsibilities.
During the first half of the 16th century, reformation rapidly spread in Livonia. Initially Protestant propagators succeeded only in cities, but later also at the countryside and territories of the Livonian Order. One of the prisoners of the Bauska Castle's prison from 1536 to 1538 was the promulgator of Martin Luther's ideas, Burkard Waldis. In 1527 the play "De Parabell vam vorlorn Szohn" ("Parable of the prodigal son") written by Waldis was staged in Riga. It is considered to be one of the earliest examples of Reformation drama in German literature. During his term as a prisoner of the Bauska Castle Waldis started to translate psalms to German adapting or composing melodies for them.
In the summer of 1556, a military conflict occurred between the Archbishopric of Riga and the Livonian Order that was the last fight over the supreme power in the country. In August 1557, Poland formally declared war on the Order. The Lithuanian army gathered along the border of Livonia with the Polish army and forces of the Duke of Prussia joining them. The army of the Livonian Order and its allies consisted of 7000 troops, several thousands of Latvian peasants and mercenaries who were housed in the surroundings of Bauska. The Valmiera Landtag adopted a new draft act of settlement that had to be brought to Vilnius by governors of the Order. The Order's delegates stayed in the Bauska Castle for the whole month of July 1557, because they did not receive the permission for entry. Only on 31 August, the delegation arrived in Poswol (at present Pasvalys) where in the presence of the Duke of Prussia and envoys of the Kaiser of Germany Sigismund II Augustus dictated his Peace Treaty.
Along with the beginning of the Livonian War, on 31 August 1559 a protection agreement was concluded in Vilnius and signed by the Master of the Livonian Order, Gotthard Kettler and the Lithuanian Chancellor, Mikolaj Radziwiłł. Poland promised to help Livonia in the battle against Russia. As a form of payment, it required to temporarily transfer castles and Livonian provinces along the border into ownership of Poland. The Bauska Order Castle was transferred to the viceroy of the King of Poland at the end of 1559, but in 1561 it was regained from the Poles by the last Archbishop of Riga, Wilhelm of Brandenburg in exchange for Koknese.