Concordia was the deified principle of harmony among the citizens of the state — the goddess whose presence meant the absence of civil discord, whose departure meant the strife that the Romans, after the experience of their long civil wars, had learned to dread above all other political conditions. Her cult was anciently established. Her great temple in the Forum, at the foot of the Capitoline hill, was traditionally founded by the dictator Camillus in 367 BCE to commemorate the reconciliation of the patricians and plebeians (after the long social struggle that had at last produced the Licinian-Sextian rogations admitting plebeians to the consulship); the temple was rebuilt several times, most magnificently by Tiberius in 7 CE (the so-called Temple of Concordia Augusta), and it was one of the most architecturally distinguished buildings of the imperial Forum.

Concordia received state sacrifices on January 16 (the dedication-day of Tiberius's reconstruction), at moments of political reconciliation, and at the conclusion of foreign wars. Her image appeared on coinage of nearly every emperor; the legend Concordia Augusta was a standard imperial slogan, indicating the harmony of the imperial family or of the state. She was depicted as a matron holding a patera (the offering-bowl) and a cornucopia, sometimes also an olive branch, occasionally accompanied by Pax (Peace, her near-relation). Her Greek counterpart was Homonoia, who had been honored with a similar (though less elaborately developed) cult in the Hellenistic cities; the Roman Concordia owed something to this Hellenistic example but went considerably beyond it in cultic elaboration.