"The logistics deployed by the Romans to feed themselves is fascinating," said Orietta Rossini, curator of the Ara Pacis exhibition, emphasising how hard it was to keep happy a capital of one million people－the biggest in history before the industrial revolution hit London.

The key lay in turning conquered Egypt into the empire's granary and ensuring wheat was transported cheaply to Rome all year round.

Private shipowners would carry up to 500 tonnes of wheat between Alexandria and Rome under the strict supervision of the state in an early example of today's partnerships between the private and public sectors, Rossini said.

This made the emperor "the sole distributor of daily bread, the only one responsible for the supply of provisions". Augustus boosted his popularity by distributing 35 kilos of wheat a month free to 20,000 citizens-freemen over 17 years old.

Egypt's role was later passed on to the empire's African provinces, with grain shipped from Carthage in Tunisia to Rome's Ostia port in just three days and nights. Wine, sold at rock-bottom prices, was also imported, along with oil and meat.

The wealthy may have gone out of the way to impress with exotic dishes, but the empire's leaders were fond above all of fruit and vegetables: Emperor "Tiberius loved cucumber, while Augustus loved asparagus", Rossini said.

Samples of carbonized foodstuffs discovered during excavations at the ancient town of Herculaneum-destroyed along with Pompeii by the eruption of Mount Vesuvius in AD 79-are on display at the exhibition, including wizened Roman-era figs.

The much-lauded "Mediterranean diet" began here: broad beans, peas, lentils and onions went in stews, with pine nuts, dates and almonds thrown in. Cumin, coriander, sesame and mint seeds were used to spice up dishes.

The globalization of foodstuffs seen in today's supermarkets was already in action, with wine imported from Gaul and Cyprus, oil from Andalusia, honey from Greece and prized garum－the fermented fish sauce which drove Romans crazy－from Portugal.

Food was such an important commodity that Emperor Diocletian, who ruled from 284 to 305, imposed price controls. But some dishes remained beyond the household budget for some－with chicken a particularly expensive and rare treat.

While a baker would on average earn 50 pieces of silver a day, he would have to spend 60 to buy two chickens, 30 for a half a litre of Falernian wine from the Bay of Naples, 12 for 300 grams of pork and four for 25 figs.