Pope Urban I, also known as Saint Urban (175?–230), was the bishop of Rome from 222 to 23 May 230. He was born in Rome and succeeded Callixtus I, who had been martyred. It was believed for centuries that Urban I was also martyred. However, recent historical discoveries now lead scholars to believe that he died of natural causes.

Pope Callixtus I, also called Callistus I, was the bishop of Rome from c. 218 to his death c. 222 or 223. He lived during the reigns of the Roman emperors Elagabalus and Alexander Severus. Eusebius and the Liberian catalogue list his episcopate as having lasted five years (217–222). In 217, when Callixtus followed Zephyrinus as Bishop of Rome, he started to admit into the Church converts from sects or schisms. He was killed for being Christian and is venerated as a saint by the Catholic Church.