From the martyrology:
"At Rome, St. Anicetus, pope and martyr, who received the palm of martyrdom in the persecution of Marcus Aurelius Antoninus and Lucius Verus."
St Anicetus was Pope between around 150-167.
During his pontificate St Polycarp of Smyrna, a disciple of John the Evangelist, visited Rome to discuss the celebration of Passover with the Pope, marking the start of the controversy between the Eastern and Western Churches over the date of Easter. The two agreed to differ and Pope St Anicetus granted St Polycarp and the Church of Smyrna the ability to retain the date to which they were accustomed.
St Anicetus was the first pope to condemn heresy by forbidding Montanism. He also actively opposed the Gnostics and Marcionism.
His feast is celebrated on April 20 in the Novus Ordo calendar.