Pope St. Clement I, was the third successor of Peter, after Linus and Anacletus. He was also the first of the Apostolic Fathers.

The Apostolic Fathers were Christian writers of the first and second centuries who were believed to have had personal relationships with the Apostles or were significantly influenced by them, such that their writings echoed genuine Apostolic teaching. These writings form a link between the New Testament and the later literature of the second century.

Irenaeus, the Bishop of Lyons, attested that Clement "had seen the blessed Apostles," "had been conversant with them," and "might be said to have the preaching of the apostles still echoing [in his ears], and their traditions before his eyes". Clement is known for his letter to the Corinthians, where he addressed issues of unity and submission to authority.

The writings of the Apostolic Fathers offer a valuable glimpse into the Christian community in the era following the death of St. John. Their works, often in the form of epistles, address specific needs of individuals or local churches, providing guidance and fostering unity. These letters were highly esteemed by early Christians, with some even being regarded as having almost canonical authority.

Around 95, Clement wrote a letter to the Christians in Corinth, Greece, settling disputes. This letter is an important historical document and is the earliest known example of Rome intervening authoritatively in the affairs of another apostolic church. The letter also details the deaths of Peter and Paul in Rome.

Clement was the pontiff from 88-97, which ended in his martyrdom. Clement’s successes irritated Emperor Trajan, who condemned him to the mines of Crimea, Ukraine.

Clement opened up a spring in the mines and evangelized so well that seventy-five new churches were built in that area. For this, Clement was tied to an anchor and cast into the sea. His remains were discovered by Sts. Cyril and Methodius and transferred to Rome.