Maximilian Kaller (10 October 1880 – 7 July 1947) was Roman Catholic Bishop of Ermland () in East Prussia from 1930 to 1947. However, de facto expelled from mid-August 1945, he was a special bishop for the homeland-expellees until his death. Early life Kaller was born in Beuthen (Bytom), Prussian Silesia, into a merchant family, the second of eight children. With the population of Beuthen being of German and Polish ethnicity he grew up bilingual in German and Polish. He graduated from the Gymnasium in 1899 with Abitur and started theological studies in Breslau (today's Wrocław) at the episcopal see of his then home Prince-Bishopric of Breslau. There he was consecrateda priest in 1903. He was the chaplain in the parish of Groß Strehlitz (today's Strzelce Opolskie) in the Breslau diocese. Between 1905 and 1917, he practised as a missionary priest at St. Boniface parish in Bergen on Rügen Island in the Hither Pomeranian Catholic diaspora within Breslau's Prince-Episcopal Delegation for Brandenburg and Pomerania. He raised the necessary donations to erect St. Boniface Church there in 1912. From 1917, he was the priest at Berlin's second oldest Catholic Church, Saint Michael's Garrison Church. Career as prelate and bishop In 1926, he succeeded Robert Weimann (1870–1925) as Apostolic Administrator of Schneidemühl (today's Piła). Kaller's jurisdiction comprised Catholic parishes of the dioceses of Chełmno and of Gniezno-Poznań, which had been separated from their episcopal sees by the new Polish border in 1918 and 1920, respectively. On Kaller's instigation, the seat of the apostolic administration had been moved from Tütz (Tuczno) to Schneidemühl on 1 July 1926. Following the Prussian Concordat () of 1929, some Catholic dioceses and jurisdictions in Northern, Middle and Eastern Germany had been reorganised. In 1930, the Apostolic Administration of Tütz was reconstituted as the Territorial Prelature of Schneidemühl (, , existing until 1972, and from 1945 under apostolic administrators) with Kaller being promoted to prelate. On 2 September 1930, Kaller was invested as bishop of the Roman Catholic Diocese of Ermland (an archdiocese since 1992) by Pope Pius XI and consecrated in Schneidemühl, afterwards taking the episcopal see in Frauenburg (today's Frombork). Franz Hartz succeeded Kaller as Prelate of Schneidemühl. From 1925, Ermland diocese comprised all of the Prussian Province of East Prussia in its borders of 1938. In the year of Kaller's investiture, his diocese, which had turned exempt in 1566 when its original metropolitan Archbishopric of