Rex Sacrorum

In ancient Roman religion, the rex sacrorum (also sometimes rex sacrificulus) was a senatorial priesthood reserved for patricians. Although in the historical era the pontifex maximus was the head of Roman state religion, Festus says that in the ranking of priests, the rex sacrorum was of highest prestige, followed by the flamines maiores. The rex was based in the Regia.

During the Roman Republic, the rex sacrorum was chosen by the pontifex maximus from a list of patricians submitted by the College of Pontiffs. A further requirement was that he be born from parents married through the ritual of confarreatio, which was also the form of marriage he himself had to enter. His wife, the regina sacrorum, also performed religious duties specific to her role. Marriage was thus such a fundamental part of the priesthood that if the regina died, the rex had to resign.

The rex sacrorum wore a toga, the undecorated soft "shoeboot" (calceus), and carried a ceremonial ax; as a priest of archaic Roman religion, he sacrificed capite velato, with head covered. The rex held a sacrifice on the Kalends of each month. On the Nones, he announced the dates of festivals for the month. On March 24 and May 24, he held a sacrifice in the Comitium.

The rex sacrorum was a feature of Italic religion and possibly also Etruscan. The title is found in Latin cities such as Lanuvium, Tusculum, and Velitrae. At Rome the priesthood was deliberately depoliticized; the rex sacrorum was not elected, and his inauguration was merely witnessed by a comitia calata, an assembly called for the purpose. Like the flamen Dialis but in contrast to the pontiffs and augurs, the rex was barred from a political and military career. He was thus not a "decayed king"; rather, after the overthrow of the kings of Rome, the office of rex sacrorum fulfilled at least some of the sacral duties of kingship, with the consuls assuming political power and military command, as well as some sacral functions. It is a matter of scholarly debate as to whether the rex sacrorum was created during the formation of the Republic, as Arnaldo Momigliano argued, or had existed in the Regal period. Another Roman priest given the title "king" was the rex Nemorensis.