Flamen (250–260 AD)
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 axe; 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.
Regina sacrorum 
As the wife of the rex sacrorum, the regina sacrorum ("queen of the sacred rites") was a high priestess who carried out ritual duties only she could perform. On the Kalends of every month, the regina presided at the sacrifice of a sow (porca) or female lamb (agna) to Juno. The highly public nature of these sacrifices, like the role of the Vestals in official Roman religion, contradicts the commonplace notion that women's religious activities in ancient Rome were restricted to the private or domestic sphere. Unlike the Vestals, however, the regina sacrorum and the flaminica Dialis (the wife of the flamen Dialis or high priest of Jupiter) were complements to a male partner; these two priesthoods were gender-balanced and had shared duties.
While performing her rituals, the regina wore a headdress called the arculum, formed from a garland of pomegranate twigs tied up with a white woolen thread. The rex and regina sacrorum were required to marry by the ritual of confarreatio, originally reserved for patricians, but after the Lex Canuleia of 445 BC, it is possible that the regina could have been plebeian.
Inscriptions record the names of a few reginae sacrorum, including Sergia Paullina, the wife of Cn. Pinarius Cornelius Severus, shortly before 112 AD, and Manlia Fadilla around the 2nd/3rd century AD.
In popular culture 
- "The King of Sacrifices" by John Maddox Roberts appears in The Mammoth Book of Historical Detectives, edited by Michael Ashley. (Carroll & Graf Publishers, 1995) ISBN 0-7867-0214-1
- Jörg Rüpke, Religion of the Romans (Polity Press, 2007, originally published in German 2001), p. 223 online.
- Festus on the ordo sacerdotum, 198 in the edition of Lindsay.
- Gary Forsythe, A Critical History of Early Rome: From Prehistory to the First Punic War (University of California Press, 2005), p. 136 online.
- Arnaldo Momigliano, "The Origins of the Roman Republic", in Quinto contributo alla storia degli studi classici e del mondo antico (Edizioni di storia e letteratura, 1975), vol. 1, p. 311, citing Livy 40.42 and Dionysius Halicarnassus 5.1.4.
- Kurt A. Raaflaub, Social Struggles in Archaic Rome: New Perspectives on the Conflict of the Orders (Blackwell 2005, originally published 1986), p. 223 online.
- Rüpke, Religion of the Romans, p. 223.
- Although scholars agree that this applied to the rex sacrorum, the requirement that the priest resign if his wife should die is better documented for the Flamen Dialis.
- Norma Goldman, "Roman Footwear" and "Reconstructing Roman Clothing", in The World of Roman Costume (University of Wisconsin Press, 1994), pp. 125 and 216 online.
- Mary Beard, J.A. North, and S.R.F. Price, Religions of Rome: A History (Cambridge University Press, 1998), p. 56.
- See for instance Livy 2.2.1.
- Tim Cornell, The Beginning of Rome: Italy and Rome from the Bronze Age to the Punic Wars (Routledge, 1995), pp. 234–235 online; Momigliano, "The Origins of the Roman Republic", pp. 311–312 online.
- Emily A. Hemelrijk, "Women and Sacrifice in the Roman Empire," in Ritual Dynamics and Religious Change in the Roman Empire. Proceedings of the Eighth Workshop of the International Network Impact of Empire (Heidelberg, July 5–7, 2007) (Brill, 2009), pp. 258–259 online, citing Macrobius, Saturnalia 1.15.19.
- Celia E. Schultz, Women's Religious Activity in the Roman Republic (University of North Carolina Press, 2006), pp. 79–81.
- Servius, note to Aeneid 4.137; pomegranate = malus Punica, "Phoenician apple."
- Michael Lipka, Roman Gods: A Conceptual Approach (Brill, 2009), pp. 182–183.
- Jörg Rüpke, Fasti sacerdotum: A Prosopography of Pagan, Jewish, and Christian Religious Officials in the City of Rome, 300 BC to AD 499 (Oxford University Press, 2008, originally published in German 2005), pp. 223, 783, 840.