Felix II is generally considered an antipope rather than a pope. In 356 he was raised from the archdeaconate of Rome to the Papal chair, when Liberius was banished by the emperor Constantius for refusing to subscribe the sentence of condemnation against Athanasius. Felix's election was contrary to the wishes both of the clergy and of the people, and the consecration ceremony was performed by certain prelates belonging to the court. In 357, at the urgent request of an influential deputation of Roman ladies, Constantius agreed to the release of Liberius on the condition that he signed the semi-Arian creed. Constantius also issued an edict to the effect that the two bishops should rule conjointly, but Liberius, on his entrance into Rome in the following year, was received by all classes with so much enthusiasm that Felix found it necessary to retire at once from Rome.

Regarding the remainder of his life, little is known, and the accounts handed down are contradictory, but he appears to have spent the most of it in retirement at his estate near Porto. He died in 365, and (on what grounds it is impossible to determine) was enrolled amongst the number of martyrs, his day being July 22. In the reign of Gregory XIII, the claim of Felix to rank among the popes was discussed, and in order to discover whether any miraculous help was to be found to aid in the decision of the question, his sarcophagus was opened. It was said the words "Pope and Martyr" were found inscribed on his body, but this supernatural testimony is in contradiction to that of the earlier authorities of the church.

Text from the 9th edition (1879) of an unnamed encyclopedia.