A Dictionary of Greek and Roman biography and mythology

that is, the baker, a surname of Jupiter at Rome, where its origin was thus related : when the Gauls were besieging Rome, the god suggested to the besieged the idea of throwing loaves of bread among the enemies, to make them believe that the Romans had plenty of provisions, and thus cause them to give up the siege. (Ov. Fhast. 6.350, 394 ; Lactant. 1.20.) This surname shows that there existed a connection between Jupiter, Vesta, and the Penates, for an altar had been dedicated to Jupiter Pistor on the very day which was sacred to Vesta.

[L.S]