Little is known about St. Felix I prior to his papacy. Elected on January 5, 269 to replace St. Dionysius, Felix’s New Year’s Resolution that year was probably, “Be a good pope.” The Liber Pontificalis credits Felix I with a decree that Mass should be regularly said over the tombs of martyrs. Scholars say there was likely no such decree, but it's attributed to him only because the practice began somewhere around Felix’s time. Some have called Felix a martyr, but no evidence exists to suggest that. He died on December 30, 274, and was buried in the cemetery of St. Calixtus. His feast day is celebrated on May 30. 

Pope St. Felix I was known most for writing a valuable letter on the person of Christ and his unity with the Father. The bishop of Antioch, Paul of Samosata, was given the boot by his brother bishops after he preached the Adoptianist heresy, a belief that Jesus was a mere man who achieved a perfect union of his will with the Father, and therefore earned deification. Those bishops convened, kicked Paul out of office, then sent a letter to Rome recounting what had happened. Felix gave two thumbs way up to his brothers in the East, writing a letter in response saying so.

Fun fact: Despite Felix’s help, the bishops in the East still dealt with pushback from the deposed Paul, even though his replacement (Domnus) had already been found. The issue was put before the Roman emperor, Aurelian, to decide which should be recognized as the true bishop. Aurelian basically said, “What does the pope say?” and deferred to Felix. So, since Domnus was recognized as a valid bishop and head of Antioch by the pope, he won the dispute and we have concrete proof that papal supremacy over the Church was recognized at that time even by non-Christians.

In 270, the Chinese invented gunpowder, creating it out of sulfur, charcoal, and potassium nitrate. There were no muzzleloaders to go with the powder, though. Apparently the new creation was only used for fireworks.