William the Younger, Duke of Brunswick

William
Duke of Brunswick-Lüneburg Prince of Lüneburg
Reign	1559 – 20 August 1592
Predecessor	Ernest I
Successor	Ernest II
Born	(1535-07-04)4 July 1535
Died	20 August 1592(1592-08-20) (aged 57)
Spouse	Dorothea of Denmark ​ (m. 1561)​
Issue	Sophia, Margravine of Brandenburg-Ansbach Ernest II, Duke of Brunswick-Lüneburg Elisabeth, Countess of Hohenlohe-Langenburg Christian, Duke of Brunswick-Lüneburg Augustus I, Duke of Brunswick-Lüneburg Dorothea, Countess Palatine of Zweibrücken-Birkenfeld Clara, Countess of Schwarzburg-Frankenhausen Anne Ursula of Brunswick-Lüneburg Margaret, Duchess of Saxe-Coburg Frederick IV, Duke of Brunswick-Lüneburg Marie of Brunswick-Lüneburg Magnus of Brunswick-Lüneburg George, Duke of Brunswick-Lüneburg John of Brunswick-Lüneburg Sybille, Duchess of Brunswick-Lüneburg
House	Welf
Father	Ernest I, Duke of Brunswick-Lüneburg
Mother	Sophia of Mecklenburg-Schwerin

William (4 July 1535 – 20 August 1592), called William the Younger (German: Wilhelm der Jüngere), was Duke of Brunswick-Lüneburg and Prince of Lüneburg from 1559 until his death. Until 1569 he ruled together with his brother, Henry of Dannenberg.

Born into the House of Welf, ruling family of the Principality of Brunswick-Lüneburg, William was the third son of Ernest I, Duke of Brunswick-Lüneburg and his wife, Duchess Sophia of Mecklenburg-Schwerin (1507-1541).^[1]

In 1582, William began suffering from fits of insanity. These fits caused his wife Dorothea to flee him in 1584 for her own safety.

On 12 October 1561 he married Princess Dorothea of Denmark (29 June 1546 Kolding–6 January 1617 Winsen), the youngest daughter of Christian III of Denmark and his wife, Dorothea of Saxe-Lauenburg.^[2]

William and Dorothea had:

• Sophie of Brunswick-Lüneburg (30 October 1563 – 1639); married George Frederick, Margrave of Brandenburg-Ansbach.
• Ernest II, Duke of Brunswick-Lüneburg (31 December 1564 – 2 March 1611)^[1] Prince of Lüneburg from 1592 to 1611.
• Elisabeth of Brunswick-Lüneburg (19 October 1565 – 17 July 1621); married Frederick, Count of Hohenlohe-Langenburg.
• Christian, Duke of Brunswick-Lüneburg (19 November 1566 – 8 November 1633)^[1] Prince of Lüneburg from 1611 to 1633.
• Augustus the Elder, Duke of Brunswick-Lüneburg (18 November 1568 – 1 October 1636)^[1] Prince of Lüneburg from 1633 to 1636.
• Dorothea of Brunswick-Lüneburg (1 January 1570 – 15 August 1649); married Charles I, Count Palatine of Zweibrücken-Birkenfeld.
• Clara of Brunswick-Lüneburg (16 January 1571 – 18 July 1658); married William, Count of Schwarzburg-Blankenburg.
• Anne Ursula of Brunswick-Lüneburg (22 March 1572 – 5 February 1601)
• Margaret of Brunswick-Lüneburg (6 April 1573 – 7 August 1643); married John Casimir, Duke of Saxe-Coburg.
• Frederick IV, Duke of Brunswick-Lüneburg (28 August 1574 – 10 December 1648)^[1] Prince of Lüneburg from 1636 to 1648.
• Marie of Brunswick-Lüneburg (21 October 1575 – 8 August 1610)
• Magnus of Brunswick-Lüneburg (30 August 1577 – 10 February 1632)
• George, Duke of Brunswick-Lüneburg (17 February 1582 – 12 April 1641)^[1] Prince of Calenberg 1635–1641
• John of Brunswick-Lüneburg (23 June 1583 – 27 November 1628)
• Sybille of Brunswick-Lüneburg (3 June 1584 – 5 August 1652); married Julius Ernest, Duke of Brunswick-Lüneburg.

William died on 20 August 1592, aged 57. He is interred, along with his wife, in the St. Marien Church in Celle, Lower Saxony, Germany.^[3]

After his death, his wife, Duchess Dorothea became regent for their underaged son, George, Duke of Brunswick-Lüneburg.

• Pastrnak, Patrik (2023). Dynasty in Motion: Wedding Journeys in Late Medieval and Early Modern Europe. Routledge.
• Ward, A.W.; Prothero, G.W.; Leathes, Stanley, eds. (1934). The Cambridge Modern History. Vol. XIII. Cambridge at the University Press.