Antipope Felix II

https://en.wikipedia.org/wiki/Antipope_Felix_II

Antipope Felix, (died November 22, 365) was a Roman archdeacon in the 4th century who was installed irregularly in 355 as an antipope and reigned until 365 after Emperor Constantius banished the current pope, Liberius. Constantius, following the refusal of the laity to accept Felix, attempted to have them co-rule, but Felix was forced to retire. He was resented in his lifetime but has enjoyed a more popular memory since. Antipope, in the Roman Catholic church, described any figure attempting to oppose the legitimately elected Bishop of Rome, with Felix being among the unsuccessful.