[1][2] According to one version his legend, he was born to a noble Roman family, entered military service and reached the rank of officer when he was converted to Christianity by saints Faustinus and Jovita.

In the eleventh century, the Datiana Historia, written by an anonymous author, states that Calimerius was flung into a well as revenge for having baptized so many pagans.

[1] The same source includes the detail that Calimerius was a Greek raised in Rome, as well as the fact that he was a disciple of Telesphorus, although both claims may be historically doubtful.

[1] Another legend states that he was a Roman of noble origin, who, after serving in the military, was converted by Saints Faustinus and Jovita and was elected bishop of Milan.

[5] As Hippolyte Delehaye writes, "To have lived amongst the Saviour's immediate following was ... honorable ... and accordingly old patrons of churches were identified with certain persons in the gospels or who were supposed to have had some part in Christ's life on earth.