Calocerus was a 2nd-century Christian priest and soldier from Brescia. Serving as an officer in the Roman army during the reign of Hadrian, he was stationed in Lombardy. His religious conversion was reportedly inspired by the steadfastness of Saints Faustinus and Jovita. After his conversion, he is said to have influenced Secundus of Asti. He eventually traveled to Albenga, where he preached and was ultimately martyred.