(Johann Sigismund; 8 November
– 23 December
) was a Prince-elector
of the Margraviate of Brandenburg
from the House of Hohenzollern
. He also served as a Duke of Prussia
John Sigismund was born in Halle an der Saale to Joachim Frederick, Elector of Brandenburg, and his first wife Catherine, Princess of Brandenburg-Küstrin. He succeeded his father as Margrave of Brandenburg in 1608. He gave the Reichshof Castrop to his teacher and educator Carl Friedrich von Bordelius. John Sigismund received the territories of Cleves, Mark, and Ravensberg in the Treaty of Xanten in 1614. He succeeded his father-in-law Albert Frederick as Duke of Prussia in 1618, but died the following year.
John Sigismund's most significant action was his conversion from Lutheranism
. He was probably won over to the faith during a visit to Heidelburg
in 1606, but it was not until 1613 that he publicly took communion
according to the Calvinist rite. The vast majority of his subjects in Brandenburg remained deeply Lutheran, however, and after the Elector and his Calvinist court officials drew up plans for mass conversion of the population to the new faith in February 1614 there were serious protests. Resistance was so strong that in 1615, John Sigismund backed down and relinquished any attempt at forcible conversion, allowing his subjects to be either Lutheran or Calvinist according to the dictates of their own consciences. Henceforward, Brandenburg-Prussia would be a bi-confessional state.
Family and children
On 30 October
, John Sigismund married Anna of Prussia
, daughter of Albert Frederick, Duke of Prussia
(1553–1618). They were parents to eight children:
- George William (13 November, 1595 – 1 December, 1640). His successor.
- Anne Sophia of Brandenburg (15 March, 1598 – 19 December, 1659). Married Frederick Ulrich, Duke of Brunswick-Lüneburg.
- Maria Eleonora of Brandenburg (11 November, 1599 – 28 March, 1655). Married Gustavus Adolphus of Sweden. They were parents of Christina of Sweden.
- Catharina of Brandenburg (28 May, 1602 – 27 August, 1644). Married first Gabriel Bethlen, Prince of Transylvania and secondly Franz Karl of Saxe-Lauenburg.
- Joachim Sigismund of Brandenburg (25 July, 1603 – 22 February, 1625).
- Agnes of Brandenburg (31 August, 1606 – 12 March, 1607).
- John Frederick of Brandenburg (18 August, 1607 – 1 March, 1608).
- Albrecht Christian of Brandenburg (7 March – 14 March, 1609).