The late-Roman Codex Theodosianus, a compilation of Roman laws, states that during expeditions a Roman soldier should be supplied with "buccellatum ac panem, vinum quoque atque acetum,
sed et laridum, carnem verbecinam." or "hardtack and bread, wine too and vinegar, but also bacon and mutton." (VII.4.6). Soldiers were supposed to have the hardtack, mutton and vinegar for two days and then have a day of bread, wine and bacon. We've already seen that the Romans turned vinegar into the refreshing drink posca, learned what bacon might be eaten with and discovered two different ways of baking bread. But what of buccellatum? What is hardtack?
Hardtack is a simple biscuit made from flour, salt and water. As the name suggests, it is rock hard, baked twice at low temperatures for a very long time, ensuring that no moisture is left inside. This makes bucellatum perfect for soldiering since without moisture it takes a long time to go off - ideal for prolonged campaigns in Britain where the weather would quickly spoil bread and flour. Just as bucellatum was perfectly suited to soldiering, it was perfectly suited to soldiers too - a tooth lost to this rock hard biscuit was just another war wound. In fact, so perfect was this match that Roman soldiers came to be known as bucellarii (Photius, Bibliotheca, 80). The association between hardtack and the military continues long past ancient Rome, with hardtack being eaten by crusaders, Elizabethan sailors and by folks fighting in the American Civil War.
Bucellatum may have been eaten dry, soaked in posca or softened in a stew - no doubt soldiers found a variety of ways to make this staple more exciting. Given how long it lasts, if you cook up a batch you can try new ways of preparing it for years to come. Whilst there is no surviving recipe for Roman bucellatum, there are plenty for hardtack. All are based upon flour, salt and water, ingredients which the Roman army had in abundance and distributed to its soldiers.