John V, Duke of Saxe-Lauenburg

John V of Saxe-Lauenburg (also numbered John IV; 18 July 1439 – 15 August 1507) was the eldest son of Duke Bernard II of Saxe-Lauenburg and Adelheid of Pomerania-Stolp (1410 – after 1445), daughter of Duke Bogislaus VIII of Pomerania-Stolp. He succeeded his father in 1463 as duke of Saxe-Lauenburg.

Life The ducal residential castle in Lauenburg upon Elbe. After a fire John V reconstructed Saxe-Lauenburg's residential castle in Lauenburg upon Elbe, started in 1180–1182 by Duke Bernard I.

In 1481 John V redeemed Saxe-Lauenburg's exclave Land of Hadeln, which had been pawned to Hamburg as security for a credit of 3,000 Rhenish guilders since 1407. John V then made his son and heir apparent, Magnus, vice-regent of Hadeln, and finally regent as of 1498.

Having advanced to regent Magnus, who in 1484 had failed to conquer the rich Land of Wursten, a de facto autonomous region of free Frisian peasants in a North Sea marsh at the Weser estuary, won his father and Henry IV the Elder of Brunswick and Lunenburg, Prince of Wolfenbüttel on 24 November 1498 as allies in a second attempt to conquer Wursten. However, on 9 September 1499 the pre-emptive feud of the joint forces of Wursten, the Prince-Archbishopric of Bremen, Ditmarsh, the cities of Bremen, Buxtehude, Hamburg, and Stade against John V and Magnus turned the latter's campaign into an adventure involving heavy losses.

Mediated by Eric I of Brunswick and Lunenburg, Prince of Calenberg and Henry IV, Rode and Magnus for his father John V concluded peace on 20 January 1500.

Marriage and issue On 12 February 1464 John V married Dorothea of Brandenburg (1446 – March 1519), daughter of Frederick II, Elector of Brandenburg, and they had the following children: Adelheid (*?–died as a child*) Sophia (*died latest 1497*), on 29 November 1491 ∞ Magnus I (*1 January 1470 – 1 August 1543*) Bernard (*? – 1524*), canon in Cologne and Magdeburg Eric (*1472–20 October 1522*), as Eric II Prince-Bishop of Hildesheim (1501–1503) and as Eric I Münster (1508–1522) John (*1483–20 November 1547*), as John IV Prince-Bishop of Hildesheim (1503–1547) Anna von Sachsen-Lauenburg (1468–1504*), ∞ in 1490 John (Johannes Steitz?) of Lindow-Ruppin Frederick (*?–before 1501*) Rudolph (*?–1503*) Henry (died as a child) Catherine, Cistercian nun in Reinbek bei Hamburg Elisabeth (*1489–1541*), ∞ Duke Henry IV, Duke of Brunswick-Grubenhagen.

One of John V's illegitimate children was: (in Low Saxon, , ; died before 21 February 1549), auxiliary bishop in Münster and titular bishop of Ptolemais in Phoenicia (today's Akko), as of 23 March 1519.