Both the Liber Pontificalis (“Book of Popes”) and Church historian Eusebius list Pope St. Callixtus I as the 16th Bishop of Rome and 15th successor of St. Peter, noting that he reigned for just five years.

We don’t know when he was born or where, but Callixtus was a slave of Carpophorus for the first part if his life. Carpophorus, a real piece of work, exiled his young slave to the mines of Sardinia, but after a while Callixtus was freed. He soon became archdeacon and Number Two to his predecessor, Pope St. Zephyrinus.

Being enthusiastic and a talented organizer, Callixtus is thought to have arranged the creation of more parishes (known as “titular” churches) in Rome, and was in charge of a cemetery that’s still around today. He knew the family of St. Cecilia (patroness of music), and thanks to their donation built two titular churches there as well, now know as Santa Maria in Trastevere. It was here that tradition says Callixtus was martyred, having been thrown down a well by a pagan mob.

Callixtus I was a merciful and compassionate guy. He made some people mad -- mainly Hippolytus and Tertullian -- by admitting believers who had committed adultery and fornication into the Church after they had done proper penance. It apparently wasn’t yet settled that we don’t just say, “Hey bro, you had your chance” to grave sinners. In any case, Callixtus put it to rest, invoking Jesus’ promise to Peter that the bishops held power to bind and loose (Matt. 18:18), no matter the severity of the sin.

Fun fact: Callixtus was the first pope to have to deal with what we now know as an “antipope”. Thanks to his spat with Callixtus and Zephyrinus, Hippolytus was mad enough to set up a breakaway church, where he "reigned" as antipope for the next several years. Callixtus I, in response (probably) said, “Have fun with that.”

In 222, Roman Emperor Elagabalus and his mother were assassinated during a revolt. He was succeeded by 13-year-old Alexander Severus.