A horreum was a type of Roman warehouse or granary used to store grain, foodstuffs, and other goods. These structures were designed to protect their contents from moisture, pests, and theft, featuring thick walls and elevated floors to ensure proper ventilation.
Horreums were critical for supplying Roman cities and armies, especially during military campaigns or times of shortage.
The Horreum in Ostia, Rome’s port city, was one of the largest granaries of its time, storing vast quantities of grain to feed the city’s population and sustain its armies.