Question

Of the Romans "group of three" gods in the Archaic Triad, which one did not have a Greek counterpart?

Answer 1

The Archaic Triad consists of three Roman gods which are Jupiter, Mars, and Quirinus.

Jupiter is Zeus in Greek mythology, Mars is Ares, and the god who did not have a Greek counterpart is Quirinus. In Roman mythology and religion, Quirinus is an early god of the Roman state. In Augustan Rome, Quirinus was also an epithet of Janus, as Janus Quirinus. Quirinus was known as a god of war,  who came to be identified with the deified Romulus.

Answer 2

First, let's list the three Gods of the Archaic Triad: those were Jupiter, Mars and Quirinius.

Jupiter was the equivalent of the Greek God Zeus.

Mars was the equivalent of the Greek God Ares.

The correct asnwer is Quirinius. Quiritnius was an early Roman God and does not have a (commonly accepted) Greek counterpart.