Faced with large debts of 2.5 million guilder accumulated during the reign of his father, John George instituted a grain tax which drove part of the peasantry into dependence on a nobility that was exempt from taxation. He had Jews expelled from Brandenburg in 1573, stripped of their assets and prohibited from returning. Though a staunch Lutheran opposed to the rise of Calvinism, he permitted the admission of Calvinist refugees from the wars in the Spanish Netherlands and France. On 13 July 1574, he founded the Berlinisches Gymnasium zum Grauen Kloster, the first humanistic educational institution in Berlin. He was succeeded by his son Joachim Frederick.
Upon the death of his kinsman Albert I, Duke of Prussia in 1568, the Duchy of Prussia was inherited by the latter's underage son Albert Frederick. John George's father was a co-inheritor of the Duchy of Prussia. In 1577 the Brandenburg electors became co-regent with Duke Albert Frederick of Prussia.
Family and children
John George was married three times.
His first wife was Princess Sophie of Legnica (ca. 1525 – 6 February 1546), whom he married in 1545. They had one child together:
Thirdly, he married Princess Elisabeth of Anhalt-Zerbst (15 September [O.S. 5 September] 1563 – 5 October 1607) in 1577. They had the following children:
^Princess Sabine zu Brandenburg, Electress of Brandenburg in: ourfamilyhistories.org Archived 2016-03-04 at the Wayback Machine [retrieved 14 November 2015].
^Sabine Princess of Brandenburg in: tree.familyhistory.uk.com [retrieved 14 November 2015].