Nazarius, Celsius, Gervasius & Protasius (I cent.) were martyred under Nero. Nazarius was born in Rome to a Christian mother and a Jewish father, and baptized by St. Linus (not Santa Lucia) (get it?). He dedicated his life to helping (physically) wayward Christians. For encouraging Christian prisoners in Milan (as who wouldn’t this time of year?), including the twins Gervasius and Protase (patron saint of amino acids), he was beaten and driven out of town. He went to Gaul, where he (inexplicably) was given a 9-year-old lad, Celsius (patron saint of thermal energy), to raise in the faith, which he (explicably) did.
Sometime later N & C were nabbed by the pagans and tortured. Their tormenters threw them to whatever wild beasts inhabited Gaul at that time (Huguenots? wait, wrong century), which (explicably) refused to eat them. They (the saints not the beasts) were then tossed into the sea, but they either (a) walked on water, or (b) were hauled back on board when a freak storm came up. The soldiers were so impressed they converted to Christianity on the watery spot. N & C then went back to Milan, where G & P were (inexplicably) still in prison. All four were all beheaded, and their relics buried by a pious Milanian, and forgotten. Years later Bishop Ambrose (yes, that Bishop Ambrose) (Dec 7) was led by a vision to the saints’ relics, which he subsequently had reinterred with honor in the cathedral.
Callixtus (d. 222) was, depending upon whom you ask, an embezzler (Tertullian and Hippolytus) or unjustly accused of embezzling (Julius Africanus). He was definitely a slave, and entrusted by his owner with a bank set up especially for Christians. He was a miserable investor, however, and between that and (maybe) stealing from the till, the bank was soon rupt. He caught the first ship out of town, irregardless—sorry, regardless—of destination. His owner (Carporphorus) was one step behind and sailing faster. Seeing Carpy rowing out to his ship, Callixtus jumped into the sea to make a swim for it. “Grab him!” Carporphorus hollered, and the sailors rowed out to the fugitive, hauled him aboard, and handed him over.
Carporphorus was going to work Callixtus to death on a gristmill, but the creditors of the bank insisted he be set free so he could repay their money (thinking he might have buried some of it somewhere). Once free, Callixtus burst into the nearest Synogogue on the Sabbath and demanded they give him money. (He claimed he was confronting financiers who had defrauded him. Yeah.) They had him brought before the magistrate, and he was sentenced to work in the famous sardine mines of Sardinia (okay, tin mines). He was set free through the intercessions of the emperor’s secretly-Christian mistress, Marcia (now there’s a story!).
After all that, Callixtus cleaned up his act, and was appointed deacon and chief undertaker at a Christian cemetery. He became so well-respected that the next time they needed a pope, he was chosen. As pope he became an advocate of forgiveness of sinners (go figure), for which (as well as alleged irregularities in his Trinitarianism) he was tried for heresy by a kangaroo court that included—surprise!—Hippolytus (who believed any Christian who committed mortal sin be permanently excommunicated). Hippo denied the validity of Callixtus’ election, and had himself proclaimed pope, becoming the first anti-pope.
The schism continued after Callixtus’ death (he was thrown down a well by a pagan mob on an anti-Christian bender). Hippolytus continued to insist he was pope despite the elections of Urban I and Pontian. Pontian and Hippolytus both were arrested and sent to the sardine mines, where Hippolytus repented, Pontian forgave him (ask Alanis Morissette if that’s ironic), and both died.