John I, Duke of Mecklenburg-Stargard

John I, Duke of Mecklenburg-Stargard (1326 – between 9 August 1392 and 9 February 1393), Duke of Mecklenburg from 1344 to 1352 and Duke of Mecklenburg-Stargard from 1352 to 1392.

Life John I was probably born in 1326 as the youngest child from the second marriage of Lord Henry II "the Lion" of Mecklenburg and Anna of Saxe-Wittenberg, a daughter of Duke Albert II of Saxe-Wittenberg.

His father died in 1329, John remained under guardianship until 1344, when he came of age and began to carry a seal as a participant in the governance of Mecklenburg.

Upon the division of Mecklenburg on 25 November 1352, John was awarded the Lordships of Stargard, Sternberg, Eldenbürg (Lübz) and Ture. His first wife Rixa (background unknown) probably died soon after the wedding and the marriage remained childless.

His second wife Anna was a daughter of the Count Adolf VII of Pinneberg and Schauenburg. She probably died in 1358. John and Anna had a daughter Anna, who married Wartislaw VI of Pomerania-Wolgast on 4 April 1363.

John's third wife Agnes was the daughter of Ulrich II of Lindow-Ruppin and widow of Lord Nicholas IV of Werle. They probably married in 1358 and had five children together: John II (died between 6 July and 9 October 1416), co-regent, then Duke of Mecklenburg-Stargard, from 1408 Lord of Sternberg, Friedland, Fürstenberg and Lychen Ulrich I (died 8 April 1417), co-regent, then Duke of Mecklenburg-Stargard (1392–1417), from 1408 Lord of Neubrandenburg, Stargard, Strelitz and Wesenberg (with Lize) Rudolf (died after 28 July 1415), was initially Bishop of Skara and from 1390 as Rudolf III Bishop of Schwerin Albert I (died 1397), co-regent of Mecklenburg, from 1396 Coadjutor of Dorpat Contance (born c. 1373, died 1408)