John I of Lüneburg

John (1242–1277) reigned jointly with his brother, Albert, as the second Duke of Brunswick-Lüneburg until the partition of the duchy. John was also the first ruler of the newly created Principality of Lüneburg in 1269.

John's father, Otto the Child, was the first Duke of Brunswick-Lüneburg. After his death in 1252, John ruled the duchy jointly with his elder brother Albert. As the brothers could not agree who should govern the duchy, in 1267 they decided to divide their possession. In 1269 John received the right to choose his part. He chose the Lüneburg Land and the city of Hanover, forming the Principality of Lüneburg. Albert receive the land around Brunswick and Wolfenbüttel as well as parts of the Principality of Calenberg and around Göttingen. John thus founded the Old Line of Lüneburg and his brother the Old Line of Brunswick.

John died on 13 December 1277 and was buried in the cloister of St. Michael's Church in Lüneburg.

In 1265 John married Liutgard of Holstein-Itzehoe (d. after 28 February 1289), daughter of Gerhard I, Count of Holstein-Itzehoe, and had five children:

His illegitimate son, Henry of Brunswick (d. 23 August 1324), was a canon in Walsrode.

...
Wikipedia