Quirinus is a Sabine name for the god the Romans called Mars. He became part of the Roman pantheon. The Roman Quirinal Hill is named for Quirinus. It was part of Sabine territory when Rome absorbed it. [See Mommsen on the growth of the Quirinal community.] Although he was an important god, little is known about him or the etymology of Quirinus.
Quirinus had his own priest, the flamen quirinalis, the least of the major flamines. There were also (more important) flamines for Jupiter and Mars. Together with Quirinus, they formed an important trinity of gods worshiped in early Rome.
From the 3rd century B.C., Quirinus and Romulus refer to the same person. Following the disappearance of Romulus after 38 years as king of the Romans, he changes into the god Quirinus. The festival celebrating the ascension of Romulus, the Quirinalia, was held on February 17.
Source:Herbert Jennings Rose, John Scheid "Quirinus" The Oxford Classical Dictionary. Ed. Simon Hornblower and Anthony Spawforth. Oxford University Press 2009. Oxford Reference Online. Oxford University Press.
