Final answer:
The Royal Portal in Chartres Cathedral had multiple functions, serving as an entrance for royalty, comparing French kings to biblical kings, and depicting biblical narratives relating to Christ and Mary.
Step-by-step explanation:
The function of the Royal Portal in Chartres Cathedral was all of the above. The Royal Portal served as an entrance for royalty and high-ranking clergy, as well as a way to compare French kings to biblical kings depicted on the facade. Additionally, the Royal Portal depicted biblical narratives relating to Christ and Mary, with sculptures and carvings that conveyed these stories