In Roman mythology, Portunes (alternatively spelled Portumnes or Portunus) was a god of keys and doors and livestock. He later became associated with Palaemon and became primarily a god of ports and harbors. He protected the warehouses where grain was stored.
He had a temple of the Forum Boarium. His festival, on August 17, was the Portunalia. On this day, keys were thrown into a fire for good luck in a very solemn and lugubrious manner. His attribute was a key.
There is a temple of Portunus in Rome( pictured), in the ancient Forum Boarium by the Tiber. From here, Portunus watched over cattle-barges as they entered the city from Ostia.
The site was also a religious center housing the Temple of Hercules Victor, the Temple of Portunus, and the massive 6th or 5th century BC Great Altar of Hercules.
The Temple of Hercules Victor or Hercules Olivarius (Hercules as protector of the olive trade), is a circular 2nd century BC building in the corinthian style (capitals with acanthus leaves.)
The Temple of Portunus is a rectangular building (built between 100 and 80 B. Ionic in style (capitals with characteristic volutes).