Final answer:
The election of a French pope led to a split in the papacy due to political and nationalistic influences, resulting in rival papal courts in Rome and Avignon.
Step-by-step explanation:
The election of a French pope led to a split in the papacy primarily due to political and nationalistic influences. In the early 14th century, tensions between the French monarchy and the papacy escalated, leading to the move of the papal residence from Rome to Avignon, France. This relocation, along with the French rulers' reluctance to give up their influence over the pope, resulted in a division with rival papal courts in Rome and Avignon.