Who married John, Elector of Saxony?

John (30 June 1468 – 16 August 1532), known as John the Steadfast or John the Constant (German: Johann der Beständige), was Elector of Saxony from 1525 until 1532. He belonged to the House of Wettin.

John was notable for organising the Lutheran Church in Saxony at both governmental and administrative levels. He was assisted by Martin Luther, whose "Saxon model" for a Lutheran church was soon adopted in other territories of the Holy Roman Empire. Following the break with Rome, Luther relied on John for secular authority and financial support on behalf of a church deprived of much of its previous income.

He also played a role in the Protestation at Speyer.

Sophie of Mecklenburg, also spelled Sophia (18 December 1481 – 12 July 1503 in Torgau) was a German noblewoman. She was a Duchess of Mecklenburg by birth and by marriage Electoral Princess of Saxony.

Margaret of Anhalt (12 November 1494, Köthen – 7 October 1521, Weimar) was a member of the House of Ascania and was a princess of Anhalt by birth and by marriage Duchess of Saxony.