on the death of his brother edward iii, duke of bar at the battle of agincourt in 1415, louis inherited the dukedom and successfully defended his claim to it against that of his brother-in-law adolphe, duke of juliers and of berg, who felt that, as a clergyman, louis was not suited to inherit the dukedom and its revenues. in 1419, in order to put an end to the differences that had existed for several centuries between the dukes of bar and lorraine, louis negotiated the marriage of his grand-nephew rené of anjou to isabella, duchess of lorraine (daughter and heiress of charles ii, duke of lorraine), and entrusted them with ruling the duchy of bar in the 1420s.