The temple of the god Portunus lay on the Tiber harbour at Rome. Every August 17th, it became the centre of the festivities of the Portunalia,  

As with so many Roman festivals, the exact reason for the celebration is obscure. But the roles of the deity to whom it was dedicated — as well as the time of year the festival occurred — goes some way to solving the mystery.

Portunus’ Temple

 The Romans worshipped the god Portunus in a temple at the head of the Pons Aemilius, the oldest stone bridge in Rome — parts of which survive today. The bridge spanned the Tiber harbour, connecting the Forum Boarium with the west bank of the river, which was originally outside the city walls.

The Aemilii built Portunus’s temple. The structure still survives, and archaeologists have dated its remains to the second century BC. But a shrine to Portunus likely occupied the site from at least the fourth or third century BC.

 The Portunalia marked the anniversary of the temple’s dedication. According to Varro in his “On the Latin Language”: 

“The Portunalia was named from Portunus, to whom, on this day, a temple was built at the port on the Tiber, and a holiday instituted.” (VI.19).

But was the dedication of a temple the sole significance of the Portunalia?

 Portunus, the God of Ports

Some of the significance of the Portunalia lies in the function of Portunus himself. But it seems that the Romans attributed several roles to the god.

Primarily, the Romans connected Portunus to the sea. From the sixth century BC, he became associated with a minor Greek sea god, Palaemon. Palaemon and his mother, Leucothea (who became associated with the Roman dawn goddess Matuta), helped distressed sailors on voyages.

Vergil’s Aeneid shows how the Romans assigned Portunus a similar role to Palaemon’s, styling him as the friend of sailor’s. Vergil describes how: 

“Old Portunus, with his breadth of hand, pushed on and sped the galley to the land.” (5.241).

But Ovid also links Palaemon and Leucothea — and so Portunus — with harbours: 

“The Greeks call you Leucothea, we Matuta. Your son will have complete control of ports: Portunus to us, Palaemon in his own tongue.” (Fasti 6.545-46).

This, and the fact that the stem of the god’s name “Portus” is the Latin for port or harbour seems to seal the matter. But other evidence suggests that Portunus’s role was not that straightforward.

The God of Gateways

The Romans also regarded Portunus as a god of gateways. Cult and ritual link him to two other ancient Roman deities: Janus, the god of thresholds and gateways and his epithet Quirinus.  

The two deities have several things in common. Firstly, the Romans dedicated Janus’ temple in the Forum Holitorium on the Campus Martius on precisely the same day as that of Portunus’. Then there is the question of keys. The Romans depicted both Janus and Portunus holding keys, and Varro refers to Portunus as “Deus portuum portarumque praese’s” (“The gate and the gate president.”)

Finally, there is the role of the Flamen Portunalis in the ceremonial greasing of the arms that adorned the statue of Quirinus on the Quirinal Hill. Dumezil attributes this to the fact that one of Portunus’s roles was as the guardian of the gates of Rome. He cites Giuliano Bonfante, who claims this role traced back to the time when the ancestors of the Roman’s lived in a village set on piles on the marshy land at the edge of the Tiber. The approach to the entrance of this village was also its port. If accurate, this fact makes Portunus’s role as a god of the gateway as well as the port comprehensible.

Guardian of the Port Storehouses

Portunus’s temple lay on the very threshold of Rome and near her Tiber port – making both the harbour and the protection of Rome feasible explanations for the Portunalia. But the timing of the festival is also of some significance, for the Portunalia occurred towards the end of the wheat harvest. Wheat was the staple food in ancient Rome, so its value was beyond compare. And some of the Roman grain supply was stored in warehouses along the Tiber. 

Fowler suggests one of the customs of the Portunalia was an annual ritual where the ancient wooden keys to the storehouses were hardened in fire. This ritual establishes a connection between the festival and the safekeeping of the harvest.

So it seems that Portunus’s roles of supernatural gatekeeper and harbour master also made him by default the guardian of Rome’s harvest.

Sources

Dumezil, G (1996 ed) Archaic Roman Religion: Vol 1 and 2, John Hopkins University Press: Baltimore and London

W Warde Fowler, (1899) The Roman Festivals at the Period of the Republic, Macmillan and Co.

Price and Kearns, (2003) The Oxford Dictionary of Classical Myth and Religion. Oxford University Press

Beard, M, North, J and Price, S, Religions of Rome, Vol 2, Cambridge University Press, 2005

Ovid, (trans) A J Boyle and R. D Woodard), (2000)  Fasti. Penguin Books

Virgil’s Aeneid