There are many conflicting opinions as to the true biography of Saint Denis. A variety of ancient texts describe his life, but different details and stories of his life were debated through the Middle Ages and continue to be studied and questioned today. Most sources agree, however, that Saint Denis was the first bishop of Paris. He was sent from Rome to Gaul as a missionary by Pope Clement I. Once in France, Saint Denis built the first cathedral in the city and began converting people to Christianity. He and his two companions (Rusticus and Eleutherius) were put to death under Emperor Valerius at Montmartre due to their Christian faith. Legend says that after his execution, Denis picked up his head and carried it to the spot where he is buried today, thus choosing the spot for his followers to build the basilica. Although the image of Denis as a cephalophore (holding his own head) only dates back to seventh century accounts, this is the image used to most easily identify him in depictions since then. He is the most famous cephalophore saint other than Saint John the Baptist.
Other historians differ on how Denis’ remains came to lay where they did. Some say that Denis and his followers’ remains were obtained by a wealthy Roman woman and buried on her private estate. Later, Christian believers built the basilica over her land. Tests done by archaeologists, however, date the remains to the fourth century rather than the first. In addition, the remains of saints were thought to hold miraculous powers, and thus were divided among different regions in fragments to maximize the usage of this power. King Clovis II (son of Dagobert I) is said to have stolen an arm of St. Denis’ remains, but later returned it to the abbey in a golden encasement.
The basilica became a very popular burial site for royalty, as aristocrats believed burial in the same area as the saints would help their chances of eternal salvation. Saint Denis also became the saint called upon for aid when French royalty fell ill or faced hardship, resulting in Denis receiving credit for many successes of the French monarchy.
Some histories of Denis claim that he was actually the Biblical Dionysius, the man converted by Saint Paul in the book of Acts. This biography traces Denis from his conversion by Paul leading to his travels to Rome, where he was then sent to Gaul. This understanding of Denis’ biography derives from a combination of the Biblical Dionysius, the third century apostle Dionysius, and the fifth century Pseudo-Dionysius. This supposed direct link to Saint Paul as well as to the apostle Peter via Clement gives Denis greater significance and credo as a saint.