Pope Liberius

Pope Liberius (310 – 24 September 366) was the bishop of Rome from 17 May 352 until his death on 24 September 366. According to the Catalogus Liberianus, he was consecrated on 22 May as the successor to Julius I. He is not mentioned as a saint in the Roman Martyrology, making him the earliest pontiff not to be venerated as a saint in the Catholic Church and, along with Anastasius II, one of only two popes to be omitted from Catholic sainthood in the first 500 years of church history.

Liberius is mentioned in the Greek Menology, the Eastern equivalent to the martyrologies of the Western Church and a measure of sainthood prior to the institution of the formal Western processes of canonization.

Source: Wikipedia — https://en.wikipedia.org/wiki/Pope_Liberius