(alternatively spelled in the Latin ) was the first harbour specifically constructed to be a base for the

Roman Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of ancient Rome *''Epistle to the Romans'', shortened to ''Romans'', a letter ...

western naval fleet, the ; the eastern fleet was based in the

Port of Ravenna The Port of Ravenna ( it, Porto di Ravenna) is an Italian seaport on the North Adriatic Sea in Ravenna, Italy. It is one of the top twenty Italian ports and top forty European ports. Overview The port of Ravenna is the main port of Emilia-Romagn ...

. The port was located at

Misenum Miseno is one of the ''frazioni'' of the municipality of Bacoli in the Italian Province of Naples. Known in ancient Roman times as Misenum, it is the site of a great Roman port. Geography Nearby Cape Miseno marks the northwestern end of the Bay ...

on a peninsula at the northern end of the

Gulf of Naples The Gulf of Naples (), also called the Bay of Naples, is a roughly 15-kilometer-wide (9.3 mi) gulf located along the south-western coast of Italy (province of Naples, Campania region). It opens to the west into the Mediterranean Sea. It i ...

. Portus Julius was named in honour of Octavian's (later to become Caesar

Augustus Caesar Augustus (born Gaius Octavius; 23 September 63 BC – 19 August AD 14), also known as Octavian, was the first Roman emperor; he reigned from 27 BC until his death in AD 14. He is known for being the founder of the Roman Pri ...

) great-uncle and adoptive father,

Julius Caesar Gaius Julius Caesar (; ; 12 July 100 BC – 15 March 44 BC), was a Roman general and statesman. A member of the First Triumvirate, Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey in a civil war, and ...

and the Julian clan.

Construction of Portus Julius

During the civil wars,

Octavian Caesar Augustus (born Gaius Octavius; 23 September 63 BC – 19 August AD 14), also known as Octavian, was the first Roman emperor; he reigned from 27 BC until his death in AD 14. He is known for being the founder of the Roman Pri ...

needed a safe naval harbour in which to build and train a fleet for a campaign against

Sextus Pompeius Sextus Pompeius Magnus Pius ( 67 – 35 BC), also known in English as Sextus Pompey, was a Roman military leader who, throughout his life, upheld the cause of his father, Pompey the Great, against Julius Caesar and his supporters during the las ...

(younger son of

Pompey Gnaeus Pompeius Magnus (; 29 September 106 BC – 28 September 48 BC), known in English as Pompey or Pompey the Great, was a leading Roman general and statesman. He played a significant role in the transformation of ...

the Great) who was making frequent raids on Italy and upon the shipping routes for Rome's grain supply. To run the operation, Octavian turned to his closest and most able associate,

Marcus Agrippa Marcus Vipsanius Agrippa (; BC – 12 BC) was a Roman general, statesman, and architect who was a close friend, son-in-law, and lieutenant to the Roman emperor Augustus. He was responsible for the construction of some of the most notable build ...

Agrippa knew that Lake Averno was invisible from the surrounding sea and bay waters, and reasoned that the fleet's existence there could be kept secret from Sextus' navy until it was ready to strike. Agrippa's plan, executed from 37-36BC, was to dig a canal to connect Lake Averno to

Lake Lucrino Lucrinus Lacus or Lucrine Lake ( it, Lago di Lucrino; nap, Laco 'e Lucrine) is a lake in Campania, southern Italy. It is less than one kilometre to the south of Lake Avernus and is separated from the Gulf of Pozzuoli by a narrow strip of land. A ...

and a second, shorter canal with a hidden entrance between Lake Lucrino and the sea. A long road access tunnel, the

Grotta di Cocceio The Grotta di Cocceio (Cocceius' Tunnel) is an ancient Roman tunnel nearly a kilometre in length connecting Lake Avernus with Cumae and dating from 38-36 BC. It was burrowed through the tuff stone of Monte Grillo by the architect Lucius Cocceiu ...

, was also dug from Lake Averno north to the town of

Cumae Cumae ( grc, Κύμη, (Kumē) or or ; it, Cuma) was the first ancient Greek colony on the mainland of Italy, founded by settlers from Euboea in the 8th century BC and soon becoming one of the strongest colonies. It later became a rich Ro ...

. Agrippa's innovative strategy was validated as construction of the new fleet remained unknown to Sextus' roving fleet. When it was complete, fully outfitted and trained, Agrippa's fleet left its secret base and defeated Sextus at the

Battle of Naulochus The naval Battle of Naulochus ( it, Battaglia di Nauloco) was fought on 3 September 36 BC between the fleets of Sextus Pompeius and Marcus Vipsanius Agrippa, off Naulochus, Sicily. The victory of Agrippa, admiral of Octavian, marked the end of t ...

(off the north coast of Sicily), the decisive naval battle of the campaign.

Abandonment and new harbour at Misenum

Parco archeologico di Baia - portus Julius 2

Shortly after the successful conclusion of the war with Sextus, the first Portus Julius was abandoned, owing to accumulations of silt that compromised its navigability. With secrecy no longer a requirement, nearby

became home to a second and larger version of the naval base.Meyer Reinhold, Marcus Agrippa (1933), p. 32 The Romans built new breakwaters and the base was fed by the Aqua Augusta, an aqueduct which also supplied Cumae, Neapolis,

Pompeii Pompeii (, ) was an ancient city located in what is now the ''comune'' of Pompei near Naples in the Campania region of Italy. Pompeii, along with Herculaneum and many villas in the surrounding area (e.g. at Boscoreale, Stabiae), was buried ...

and other towns around the bay. The outer harbour behind Cape Misenum served the active vessels of the Roman navy and provided room for training exercises, while its inner counterpart (to which it was connected by a canal crossed by a wooden bridge) was designed for the reserve fleet and for repairs, and as a refuge from storms. Because of its location, the area controlled the entire Italian west coast, the islands and the

Straits of Messina The Strait of Messina ( it, Stretto di Messina, Sicilian: Strittu di Missina) is a narrow strait between the eastern tip of Sicily (Punta del Faro) and the western tip of Calabria ( Punta Pezzo) in Southern Italy. It connects the Tyrrhenian Se ...

Present state

The waters of Portus Julius may still be seen today, though much smaller since one of the original lakes of the Roman port, Lake Lucrino, was greatly reduced in size by the volcanic appearance of a large hill in the middle of the lake in the 16th century, a hill now called ("new mountain"). Shifting coastlines over the centuries have also put a number of the original harbour facilities under water; some of them may be seen from glass-bottom boats or by scuba-diving.

References

{{Archaeological sites in Campania 1st century BC in the Roman Republic Military of ancient Rome Navy of ancient Rome Roman sites of Campania Ancient Roman buildings and structures in Italy Shipyards of Italy Archaeological sites in Campania Ancient Roman buildings and structures in Pozzuoli Roman harbors in Italy Phlegraean Fields

Construction of Portus Julius

Abandonment and new harbour at Misenum

Present state

See also

References