Pope Felix I was the bishop of Rome from 5 January 269 to his death on 30 December 274.
A Roman by birth, Felix was chosen to be pope on 5 January 269, in succession to Dionysius, who had died on 26 December 268.
Felix was the author of an important dogmatic letter on the unity of Christ’s Person. He received Emperor Aurelian’s aid in settling a theological dispute between the anti-Trinitarian Paul of Samosata, who had been deprived of the bishopric Antioch by a council of bishops for heresy, and the orthodox Domnus, Paul’s successor. Paul refused to give way, and in 272 Aurelian was asked to decide between the rivals. He ordered the church building to be given to the bishop who was “recognized by the bishops of Italy and of the city of Rome” (Felix). See Eusebius, Hist. Ecc. vii. 30.
The text of that letter was later interpolated by a follower of Apollinaris in the interests of his sect.
The notice about Felix in the Liber Pontificalis ascribes to him a decree that Masses should be celebrated on the tombs of martyrs (“Hic constituit supra memorias martyrum missas celebrare”). The author of this entry was evidently alluding to the custom of celebrating Mass privately at the altars near or over the tombs of the martyrs in the crypts of the catacombs (missa ad corpus), while the solemn celebration always took place in the basilicas built over the catacombs. This practice, still in force at the end of the fourth century, dates apparently from the period when the great cemeterial basilicas were built in Rome, and owes its origin to the solemn commemoration services of martyrs, held at their tombs on the anniversary of their burial, as early as the third century. Felix probably issued no such decree, but the compiler of the Liber Pontificalis attributed it to him because he made no departure from the custom in force in his time.
Source: Wikipedia App.