Pope Saint Linus (d. 79) was the second leader of the unified Catholic Church in the city of Rome. The Catholic Church identifies Linus as the second Pope, immediately following the apostle Saint Peter, however some Protestant scholars hold Saint Linus to be the first Bishop of Rome, first appointed by Saint Paul, based upon Saint Peter's claim preserved in the Apostolic Constitutions.  Tertullian names Saint Clement as the first successor to Saint Peter, but most other accounts (except Peter's) have Linus as the first bishop of Rome following St Peter, though they vary significantly on the date of the commencement of his papacy. Most sources suggest that Linus became pope in 67, while Eusebius gives 69, the Catholic Encyclopedia 64, the Liber Pontificalis 56 and the Liberian Catalogue 55. The Vatican's 2003 Annuario Pontificio cites the year 68. The discrepancy may be explained by Linus already being Saint Peter's adjutor during his lifetime, and some of the sources may incorrectly choose this time. He was Pope for eleven to fifteen years; the Liberian Catalogue gives a duration of 12 years, 4 months and 12 days.
Saint Peter's view, preserved in the Apostolic Constitutions, comment on the appointment of Saint Linus as Rome's first Bishop. Saint Peter writes: "Now concerning those bishops which have been ordained in our lifetime, we let you know that they are these: ... Of the church of Rome, Linus the son of Claudia was the first, ordained by Paul; and Clemens, after Linus’ death, the second, ordained by me Peter." Peter's words are credible since Paul arrived in Rome prior to Peter, and therefore Paul was in a more likely position to appoint a Bishop.
The Apostolic Church Elder Irenaeus, a disciple of Polycarp (Born c. A.D. 130) and later Bishop of Smyrna, also confirms Linus' appointment. He wrote: "After the Holy Apostles founded and set the Church in order (in Rome) they gave over the exercise of the episcopal office to Linus. The same Linus is mentioned by St. Paul in his Epistle to Timothy [II Tim 4:21]. His successor was Anacletus."  Also, "The apostles, having founded and built up the Church at Rome, committed the ministry of its supervision to Linus. This is the Linus mentioned by Paul in his Epistle to Timothy." 
Almost nothing is known of his life. According to Zedler his mother was Claudia, his father Herculeanus. All of the writings which were thought to have been written by Linus actually turned out to be fiction or unprovable. The decree for women to keep their heads covered while in church is probably not issued by him, as was claimed for a long time. The apocryphal Latin account of the death of the apostles Peter and Paul is falsely attributed to Linus (it was actually written in the 6th century).
Sources also vary on the date of his death. Most suggest that he died in 79, while the Liber Pontificalis gives 67, Zedler 78, and Eusebius 81. Many sources—especially the Liber Pontificalis, but not Irenaeus—claim he died a martyr, but as there was no persecution in the time of Linus' death, most historians regard Linus' martyrdom rather improbable. Nevertheless, his memorial (feast day) is September 23, the day of his martyrdom according to the Liber Pontificalis. The same work also claims that Linus was buried on the Vatican Hill. In the 7th century an inscription was found near the confessional of St Peter, which was believed to contain the name Linus.