St. Clement was a Pope from 88 to 97 or from 92 to 101, the supposed third successor of St. Peter. He was also the first Apostolic Father, i.e. someone who was not an Apostle themselves but had contact to one and authored important early christian works, which whilst not included in the New Testament, were widely circulated and read.
The Apostolic Fathers
The Apostolic Fathers (also known as the Ante-Nicene Fathers) include, as well as St. Clement, St. Ignatius of Antioch, St. Polycarp of Smyrna, Hermas, St. Barnabas, Papias, and the anonymous authors of the Didachē (Teaching of the Twelve Apostles), Letter to Diognetus, Letter of Barnabas, and Martyrdom of Polycarp. St. Clement himself is mentioned in St. Paul’s Letter to the Philippians 4:3
The Apostolic fathers (early Byzantine painting, Artist Unknown)
He was also the (co-)author of an Epistle to the Corinthians which was written c. 96 AD in the name of the Church of Rome to deal with disturbances in the Church at Corinth. The letter is one of the earliest witnesses to the authority of the Church of Rome and was so highly regarded that it was read publicly at Corinth with the Scriptures in the second century.
Imprisonment and Martyrdom
St. Clement was imprisoned whilst on a journey to Crimea (known by the Romans as Taurica) after miraculously releasing a gushing stream of fresh water with his pickaxe, an act which led to the conversions of large numbers of Romans to the Christian faith. As punishment for this the pagan Emperor Trajan order him to be tied with an anchor around his neck and thrown into the Black Sea to drown. The anchor became his symbol, a symbol of hope, and he became a patron saint of mariners and a guardian in gales and storms. Trajan, no friend of the Christians, went on to order executed other church leaders such as Ignatius, Bishop of Antioch, and Simeon, Bishop of Jerusalem.
Relics
The relics of St. Clement are preserved beneath the high altar of the fourth-century basilica of San Clemente in Rome, built on the site of a Villa owned by an early Roman Christian, Titus Flavius Clemens, one of the first Roman senators to convert to Christianity and Consul under Domitian (reigned 81 to 96) in AD95. His house was used for Christian clandestine worship during his lifetime, since being Christian at the time was forbidden, Domitian. His faith was discovered and he was forced to resign as Consul and was executed by Domitian shortly afterwards.
Depictions of his Martyrdom
The painting in the photo below of the martyrdom of St. Clement hangs in the refectory of the Dominican priory adjoining the basilica.
The Martyrdom of St. Clement (Artist Unknown)