From OCA.org:

The Martyr Patroclus lived during the third century under the emperor Aurelian (270-275). He was a native of the city of Tricassinum (now the city of Troyes in France) and led a pious Christian life: he loved to pray, to read the Holy Scriptures, to fast and to be charitable to the poor. For this the Lord bestowed upon him the gift of wonderworking.

The emperor Aurelian summoned St Patroclus to himself and commanded him to worship idols, promising for this great honors and riches. The saint disdained idol worship saying that the emperor himself was a beggar.

“How can you call me, the emperor, a beggar?” asked Aurelian. The saint answered: “You possess many earthly treasures, but you do not have heavenly treasures. Since you do not believe in Christ and in the future life, you shall not receive the blessedness of Paradise. Therefore, you are poor.”

Aurelian sentenced him to beheading by the sword. Soldiers led him to the banks of the River Sequanum (now the Seine), but suddenly their eyes were clouded, and St Patroclus at this time went across the river on the water and began to pray on a hill on the other shore. Coming to themselves, some of the soldiers were astounded at the disappearance of the martyr and they glorified God, but others attributed the miracle to magic.

A pagan woman pointed out to the soldiers that St Patroclus was on the other bank of the river. Crossing over there, the soldiers killed the martyr. His body was buried by night by the priest Eusebius and deacon Liberius.