Reginald was the son of Theobald II, Count of Bar, and his wife Joan of Toucy.
To solve the problem, appease the clergy at Metz, and save face, Pope Boniface VIII vetoed the election but then immediately named Reginald as his choice for the bishopric.
He was the only prelate from the archdiocese of Trier to assist at the council of Vienne, called by pope Clement V to suppress the Templars.
[citation needed] Reginald de Bar is known to have owned six liturgical manuscripts all dating from the very beginning of the 14th century, probably between 1302 and 1305.
These manuscripts, especially the two volume Breviary of Verdun, are renowned for their rich illuminations, blason, marginalia and historiated initials.