According to the story, Boniface was the slave of a Roman lady named Aglaida (or Aglaia, or even Aglae). They were both pagans, and he was her lover, and they lived a rather debauched life. Apparently they tired of this lifestyle, and considered Christianity as a meaningful way of life. Aglaia had heard that possessing and venerating relics of the saints facilitated salvation, so she sent Boniface eastward on a mission to acquire some relics.
When Boniface arrived in Tarsus, he discovered some Christians being tortured in the city square. He was horror-stricken, but he was also overwhelmed by the radiant looks on the faces of the martyrs. He fell down at their feet, and prayed that he might be found worthy to suffer with them. The presiding judge asked Boniface who he was, so Boniface proclaimed himself a Christian.
And thus Boniface’s prayers were answered. He was stripped and hung upside down and beaten, and molten tin was poured down his throat. Having survived all that, and presumably spending the night in a prison cell, the next morning he was thrown into a cauldron of boiling tar. He was saved by an angel who came down from heaving and “bedewed” him (as the legend describes it) to protect him from the tar—which, however, overflowed the cauldron, splattering and burning the torturers themselves. Finally, he was beheaded, which worked.
Boniface’s companions, who had accompanied him on his trip, were able to ransom his remains and bring them back to Rome to give to Aglaida. Having thus received the relics of a saint, Agalida enshrined them, gave all her wealth to the poor, and withdrew to a monastery, where she spent fifteen years in repentance. Upon her death, she was buried beside Boniface. As the legend relates, “the sins of the one were washed away by his blood, the other was purified by her tears and asceticism.”
Boniface was introduced to the kalendar in the 12th century as a “simple” feast (the lowest rank of feast). His observance was then further demoted to a commemoration in 1955, and he was completely dropped from the General Roman Calendar in 1969. He is still commemorated in the Orthodox Church.
Boniface’s commemoration is on May 14 (December 19 in the Eastern Orthodox Church.) Because of the date of his feast, Boniface of Tarsus was one of three who, because a cold spell was believed to be common on May 12–14, were called the Ice Saints in Switzerland, Poland, Bohemia and eastern Germany, a tradition known also to Martin Luther.