Prompt
Generate an image of a mature, middle-aged man in his late 50s, dressed in traditional papal attire, including a white robe and a gold mitre, sitting on a throne-like chair with a stern yet wise expression, representing Pope Callixtus II, who was a prominent figure in the Catholic Church during the 12th century, known for his role in ending the Investiture Controversy and signing the Concordat of Worms. The background should be a simple, yet elegant, depiction of St. Peter's Basilica in Rome, where he was buried. The style should be realistic and reminiscent of medieval art.