before unleashing hell on the battlefield, the roman army demanded ritual purification of objects it considered more important than the swords themselves. they were not the offensive weapons, nor the shields, nor the standards. they were trumpets. on 23 march the tubilustrium was celebrated, the purification of the instruments of war, and on that bronze sound depended whether a legion functioned or fell apart.
to understand it you have to step into the deafening chaos of an ancient infantry clash. thousands of men shouting, the clash of metal, the dust: in that din, a general’s spoken orders did not reach anywhere. the heavy line only moved by responding to powerful acoustic signals, and the chief one was the tuba, a long straight bronze trumpet that emitted a low, penetrating bellow. it dictated when to advance, when to wheel, when to charge. it was, literally, the acoustic nerve of the legion.
roman logic carried this into the religious sphere with its usual rigour. in its lustral sense, purifying that channel placed the military season under the favour of the gods. hence the rite. the tubilustrium was held in a place called the atrium sutorium, the hall of the cobblers, and consisted of the sacrifice of a ewe lamb, with whose offering the tubae were purified. which trumpets these were is debated: varro (de lingua latina 6.14) and ovid (fasti 3.849-50) tie them to the sacred rites, and according to quasten they were the liturgical trumpets, not necessarily the campaign ones. they cleansed the instrument so as to cleanse, by extension, the army’s voice of command.
the legion did not obey the general’s voice: it obeyed the bronze bellow of the tuba. that is why they purified it before the swords.
the tubilustrium was no isolated act, and here it is worth situating it well. it closed the quinquatria, the multi-day feast in honour of minerva, and fell within the great warlike cycle that took up the entire month of march, the month of the god of war and opening of the archaic year. whoever did not go near the ceremony found out about it anyway: through the streets paraded the salii, the leaping priests of mars, dancing with their sacred shields and marking that the military season was about to open.
the very evolution of the rite deserves a note, because it reveals how the romans thought. what began as a pastoral and magical purification — cleansing the community’s tools of evil influences before the active season — ended up integrated into the most efficient military apparatus of antiquity. religion was no ornament separate from the state: it was another layer of its workings. purifying the trumpets was as much part of preparing for war as sharpening the swords or shoeing the horses.
and hence the close. once the tubas were purified, the machinery was ready to take the field. for the peoples on the other side of the frontiers — gauls, germans, britons — that metallic hum cutting through the mist was no ritual music or roman folklore. it was the last warning. it meant the shield wall was about to set itself in motion, and there was no longer any time to pray to anyone.
