Researchers analysed bone samples from 22 skeletons found in the Catacombs of St Callixtus on the Appian Way, which was used from the 3rd to 5th centuries AD. In total, around half a million tombs are believed to be housed in the catacombs of Rome.
The researchers looked at collagen in the bones of the skeletons, specifically looking for their carbon and nitrogen stable-isotope content, which helps to indicate the kind of diet people had.
The 22 skeletons examined all appeared to come from the same community and indicated that the people shared the same eating habits, the researchers found.
Compared with other Roman and Mediterranean skeletons these bones had higher rates of nitrogen but lower levels of carbon, suggesting that they ate more freshwater fish.
On average, freshwater fish appeared to account for 30 per cent of the diet of these early Roman Christians.
The research team said, “While distancing themselves from Jewish food taboos and generally avoiding meat derived from pagan sacrifices, the early Christians are normally hypothesised to have eaten the same food as their non-Christian Roman contemporaries,” reports the Times.
“Within the larger context of what is currently known about Roman dietary habits, the inclusion of freshwater fish therefore comes as unexpected and raises questions about the social origins of Christianity as well.
“When Romans ate fish at all, they are normally believed to have consumed sea fish. Freshwater fish has not been considered as an essential ingredient in the classical Roman diet.”
At the beginning of the 4th century AD, Emperor Diocletian attempted to fix the price of freshwater fish at one third of marine fish, allowing the poor to eat it. Freshwater fish in Rome most likely came from the river Tiber and would have been a free or cheap source of food.
Leonard Rutgers from the Journal of Archaeological Science, who led the team of researchers, said their findings showed “that at least the small selection of early Christians analysed were all simple folk, suggesting that the inclusion of freshwater fish is indicative of a relative lack of wealth rather than of religiously motivated ascetic behaviour”.