Horrea Grandi

About

Ostia's largest and most important grain warehouse, with storage capacity for an estimated 6,000 metric tons of grain (about a year's dole for 16,000 people). Original construction begun under Claudius (reign 41-54 CE) -- identifiable by the characteristic rough-faced opus rusticum tufa-block east and west walls -- with expansion under Nero. That Julio-Claudian building, central to Rome's grain-supply chain (annona), was standing and in active use at 117 CE. It was substantially rebuilt in brick with an added first floor and extra storage cells in a later phase spanning the late 2nd-early 3rd centuries CE (Commodan/Severan), which postdates this snapshot and is not what's being marked extant here.

What happened here

Rows of identical rooms off a central courtyard, with a wide gate, a weighing station and a guard. Floors are raised on low walls so air passes underneath and grain does not sweat. Space is rented by the room or the amphora, and the operator takes a fee for storage and another for security; valuables go into strongrooms with iron doors. Everything is inventoried by clerks who are usually slaves and who are very good at it. Grain, oil, wine, marble, salt fish, timber — most of it in transit rather than stored long. Rats, damp and fire are the constant enemies and there are contracts covering all three. Around the entrance, porters wait for work by the day.

Sources

• https://www.ostia-antica.org/regio2/9/9-7.htm
• https://dererumgestarum.tumblr.com/post/620798587139506176/the-horrea-grandi-of-ostia
• https://www.ostia-antica.org/dict/topics/horrea/intro.htm
• Russell Meiggs, Roman Ostia (Oxford, 2nd ed. 1973), ch. 15