Alexander, Duke of Schleswig-Holstein-Sonderburg

Alexander, Duke of Schleswig-Holstein-Sonderburg, (20 January 1573 – 13 May 1627) was a Danish nobleman.

Alexander
Duke of Schleswig-Holstein-Sonderburg
Born	20 January 1573 Sønderborg
Died	13 May 1627(1627-05-13) (aged 54) Sønderborg- Beck
Spouse	Dorothea of Schwarzburg-Sondershausen
Issue	Ernest Günther, Duke of Schleswig-Holstein-Sonderburg-Augustenburg August Philipp, Duke of Schleswig-Holstein-Sonderburg-Beck Philip Louis, Duke of Schleswig-Holstein-Sonderburg-Wiesenburg
House	Schleswig-Holstein-Sonderburg
Father	John II, Duke of Schleswig-Holstein-Sonderburg
Mother	Elisabeth of Brunswick-Grubenhagen

Alexander was born in Sønderborg (German: Sonderburg) in Schleswig, the third son of John II, Duke of Schleswig-Holstein-Sonderburg and Elisabeth of Brunswick-Grubenhagen. Because his elder surviving brother chose Ærø as his seat, Alexander received Sønderborg upon their father's death and was in practice its second duke. Alexander died in Sønderborg.

Alexander married Dorothea of Schwarzburg-Sondershausen, daughter of John Günther I, Count of Schwarzburg-Sondershausen, on 26 November 1604 in Oldenburg. They had eleven children:

• Johann Christian, Duke of Schleswig-Holstein-Sonderburg-Franzhagen (26 April 1607 – 28 June 1653). His grandson is Louis Charles, Duke of Schleswig-Holstein-Sonderburg-Franzhagen.
• Alexander Heinrich, Duke of Schleswig-Holstein-Sonderburg (12 September 1608 – 5 September 1657)
• Ernest Günther, Duke of Schleswig-Holstein-Sonderburg-Augustenburg (14 October 1609 – 18 January 1689)
• Georg Friedrich, Duke of Schleswig-Holstein-Sonderburg (18 December 1611 – 23 August 1676)
• August Philipp, Duke of Schleswig-Holstein-Sonderburg-Beck (11 November 1612 – 6 May 1675)
• Adolph, Duke of Schleswig-Holstein-Sonderburg (2 November 1613 – 1 February 1616)
• Anna Elisabeth, Duchess of Schleswig-Holstein-Sonderburg (5 February 1615 – 19 February 1616)
• Wilhelm Anton, Duke of Schleswig-Holstein-Sonderburg (2 April 1616 – 2 April 1616)
• Sophie Katharina, Duchess of Schleswig-Holstein-Sonderburg (28 June 1617 – 22 November 1696), wife of Anthony Günther, Count of Oldenburg
• Eleonore Sabine, Duchess of Schleswig-Holstein-Sonderburg (27 February 1619 – 27 February 1619)
• Philip Louis, Duke of Schleswig-Holstein-Sonderburg-Wiesenburg (27 October 1620 – 10 March 1689)