John I of Isenburg-Limburg, "The blind Lord" (died September 29, 1312) was from 1289 Count of (Isenburg-) Limburg and the head of the House of Limburg. The core territory of the Lordship of Limburg consisted of the city of Limburg an der Lahn and several surrounding villages. In the City Chronicle of Limburg by Tilemann Elhen von Wolfhagen, written before 1402, John was referred to as the "Blind Lord." What is this name means, however, is unclear, because no sources refer to John being physically blind. Probably John had an eye disease in his old age and was thereby visually impaired. Life John’s father, Gerlach I of Limburg, had founded the House of Limburg and sought to secure dynastic connections with neighboring noble families. John’s sister Imagina was married with the Count, later King of Germany, Adolf of Nassau. His second sister Agnes was married to Henry of Westerburg, the brother of the Siegfried II of Westerburg, the Archbishop of Cologne. In 1288 John participated in the Battle of Worringen on the side of Siegfried of Westerburg. After the death of his father in the Black Forest on a military campaign of King Rudolph I of Habsburg, John inherited Lordship of Limburg. John maintained a particularly close relationship to his brother-in-law, Adolf of Nassau. He served as godparent for Adolf's children. After Adolf’s election as king, John was a regular and active supporter and rose to become one of his advisors. He sealed the 1292 pledge of the imperial portion of the city of Limburg to the Archbishopric of Cologne. In the following years, he repeatedly sealed deeds of the king, and sealed the document as a witness for King Edward I of England in his agreement with Adolf. John was delegated to arrange the marriage between Adolf’s son Robert of Nassau and Agnes, the daughter of the King Wenceslaus II of Bohemia. He was also involved in concluding of the marriage contract between Duke Rudolph I of Upper Bavaria and Matilda (Mechtilde) of Nassau (King Adolf's daughter). On July 2, 1298 John participated in the Battle of Göllheim on the side of Adolf of Nassau. Nevertheless, after the battle, he was able to win the favor of Adolf’s opponent, the new King Albert I of Habsburg. In 1303, Albert commissioned him to look for fiefs that had been wrongly taken from the empire and recover them. The children of