Clement of Rome (I Clement) and Irenaeus (To the Romans)
both attest to Peter's presence and death in Rome.
Paul makes mention of Linus, a Christian at Rome.
2 Timothy 4:21
Eubulus, Pudens, Linus, Claudia, and all the brothers
send greetings.
Irenaeus (Adversus Haereses, 3, 3, 3) tells us that the
     same Linus was Peter's first successor as bishop of Rome.
SAINT LINUS
Pope and martyr
(†67)
[Pope Linus]