During the reign of the emperor Alexander (222-235), the disturbing signs appear - the fire breaks out on the Capitol, the lightning kills the pagan priests, the sky is darkened. The Romans go outside the city walls where they encounter Christians praying together with their bishop, Callixtus, and his clergy. Consul Palmatius learns about it and informs the emperor Alexander that these Christians are certainly responsible for causing the worrying phenomena. Palmatius receives authority to force them to sacrifice.
2. [...] Tunc Palmatius accepta potestate, collecta multitudine militum, venit trans Tiberim, ubi collecta erat multitudo Christianorum cum Calixto: inter quos erat Calepodius senex presbyter: et venientes in quoddam coenaculum ingressi sunt decem milites: et cum ingressi fuissent omnes, hi decem milites subito caeci facti sunt. Respondit Calepodius senex presbyter et dixit: Filii mei, quem quaeritis? Illi autem clamabant dicentes: Accendite nobis luminaria, quia obscuratus est ante nos locus iste. Dixit autem Calepodius presbyter: Deus qui videt omnia, ipse caecavit oculos vestros. Tunc palpantes illi descenderunt caecati. [...]
Palmatius flees the scene and relates the events to Alexander who thinks that magic was involved. Palmatius convinces Alexander to organize a sacrifice to Mercury in which all the people should took part. During the sacrifice a virgin of the temple is possessed by a demon which confesses that God of Callixtus is the true God. Palmatius, struck by this event, goes to Callixtus and asks him to give him baptism.
3. [...] Dixit ei Calixtus episcopus: Noli deridere errando veritatem. Respondit Palmatius cum lacrimis, dicens: Domine, non derideo: quia cognovi in caecitate militum, et in responsione virginis, quia Dominus meus Christus tuus est. Respondit Calepodius senex et dixit ad beatum episcopum: Beatissime Pater, petenti baptismum noli denegare. [...]
Callixtus agrees. He instructs Palmatius and gives him baptism. Also his whole household converts to Christianity.
(Acta Sanctorum Octobris V, 439-440)