Fetial ritual, or the symbolic actions of a college of priests, could legitimize and formalize a state of war.
When they wanted to declare war, the pater patratus, that is, the chief of the fetials, would set out for the enemy's border.
The influence of Fetial Law on the Doctrine of Just War, however, has come to be so elusive that it is difficult to establish a correlation.
Most historians credit the origins of this doctrine to jus fetiale of the Roman collegia fetiales. This corpus juris existed from the days of the kings until the end of the Republican era.
He writes, moreover, that Roman fetial
law contains detailed prescriptions.
For a discussion of this idea in the context of the early Roman fetial
practice, see JOHN RICH, DECLARING WAR IN THE ROMAN REPUBLIC IN THE PERIOD OF TRANSMARINE EXPANSION (1976); ALAN WATSON, INTERNATIONAL LAW IN ARCHAIC ROME: WAR AND RELIGION (1993); Thomas Wiedemann, The Fetiales
: A Reconsideration, 36 CLASSICAL Q.
The fetial code and the elaborate rituals accompanying such oaths attest to their privileged status in Roman politics and religion.
Where no oaths bound Romans to behave in a certain way, they were free to act as they pleased--even barbarously by modern standards, so long as their conduct complied with the fetial code of just warfare.
The Romans would go on to establish a formal link between law and war, requiring approval from their fetials
(priests) before going to war.
were priests whose duties included determining whether
He instituted the order of the Fetials
, a college of priests whose special task it was, in Plutarch's words, to "put a stop to disputes by conference and by speech; for it was not allowable to take up arms until they had declared all hopes of accommodation to be at an end." The Fetials
endured until the late Roman Empire, providing a check of sorts on the power of the Roman state to go to war.