Robert de Lenoncourt was a French bishop, Cardinal, and diplomat. He was the son of Thierry de Lenoncourt, Seigneur de Vignory, Councillor and Chamberlain of the King, and Jeanne de Ville. He had a brother, Henry, Sire de Lenoncourt and Baron of Vignory, a sister named Jacquette, who married Jean d'Aguerre, son of the Governor of Mouzon, and a sister named Nicole, who married Érard du Châtelet. Robert's paternal uncle, also called Robert de Lenoncourt, was Archbishop of Reims.

The Diocese of Châlons is a Latin Church ecclesiastical territory or diocese of the Catholic Church in Châlons-sur-Marne, France. The diocese comprises the department of Marne, excluding the arrondissement of Reims.