On 11 July 1346, in consequence of an alliance between his father and Pope Clement VI, relentless enemy of the emperor Louis IV, Charles was chosen as Roman king in opposition to Louis by some of the prince-electors at Rhens.
For example, he organised a meeting between six of the electors in Rhens in 1338.
The next day they chose the Palatine Elector as their king at Rhens, though Wenceslaus refused to acknowledge this successor's decade-long reign.