His feast day is celebrated in both places on 15 May with fireworks and music, but 28 April is the date elsewhere.
Firmianus and Castus were devoured by lions, but Primianus tamed them and was spared.
Its citizens were dispersed across the surrounding countryside, and the inhabitants of the city of Lesina were able to take from the ruined church the relics of Primianus, Firmianus and Castus.
The citizens of Larino, once it was restored, declared war on Lesina and stormed it to regain the relics.
A notable reliquary of some of Primianus's relics is preserved in Acquaviva Collecroce.