Saint Anecitus, or Pope Anicetus, was a Syrian from the city of Emesa.
According to Irenaeus, it was during his pontificate that the aged Polycarp of Smyrna, a disciple of John the Evangelist, visited Rome to discuss the celebration of Easter with Anicetus. Polycarp and his Church of Smyrna celebrated the crucifixion on the fourteenth day of Nisan, which coincides with Pesach (or Passover) regardless of which day of the week upon this date fell, while the Roman Church celebrated Easter on Sunday—the weekday of Jesus’s resurrection. The two did not agree on a common date, but Anicetus conceded to Polycarp and the Church of Smyrna the ability to retain the date to which they were accustomed. The controversy was to grow heated in the following centuries.
According to the Annuario Pontificio, the start of his papacy may have been 153. Anicetus actively opposed Gnosticism and Marcionism. He welcomed Polycarp of Smyrna to Rome to discuss the Easter controversy. According to church tradition, Anicetus suffered martyrdom during the reign of Emperor Lucius Verus, but there are no historical grounds for this account.
Sources:
https://en.wikipedia.org/wiki/Pope_Anicetus
Martyrologium Romanum (Libreria Editrice Vaticana 2001 ISBN 88-209-7210-7)
Campbell, Thomas (1907). "Pope St. Anicetus" in The Catholic Encyclopedia. Vol. 1. New York: Robert Appleton Company.