Roman Emperior Caligula and His Legendary Lake Nemi Ships
by Kathy Warnes
Gaius Julius Caesar Augustus Germanicus, abbreviated his name to Caligula, but not his attention to his Lake Nemi ships. He had acquired the nickname Caligula when he was still a charming little boy stumping along the Rhine River with his father Germanicus in soldier’s boots several sizes too big for his feet. People started calling him Caligula which means “Little Boots” and they still called him that when he became Roman Emperor in 37 A.D. Historians are still debating whether Caligula was indeed a “mad emperor”, obsessed with murder and mayhem or a modestly progressive, responsible, ruler assassinated for strictly political reasons. Most of them agree that he funneled thousands of dollars into building several large barges for Lake Nemi.
Caligula Built Several Nemi Barges
As one of his royal passions, Emperor Caligula ordered several large barges to be built to use on Lake Nemi, a volcanic lake located about nineteen miles south of Rome, Italy. For centuries scholars and historians have debated Caligua’s reason for building the barges. Some contend that Caligula built the barges to show the rulers of Syracuse, Sicily, and the Ptolemaic rulers in Egypt that Rome could match any luxurious pleasure barges that they built. Caligula bragged that his ships were the most luxurious in the Hellenistic world- the world outside of Greece influenced by Greek culture. Other scholars argue that Caligula designed one of his ships as a floating temple to Diana and some say that the other ship may have been used as a floating palace where Caligula and his court could indulge in the depravities that history has credited to him.
The Nemi Barges Were Luxurious
Seutonius, the Roman historian described the two biggest barges as being built of cedar wood adorned with jeweled prows, rich sculpture, vessels of gold and silver, sails of purple silk, and bathrooms of alabaster and bronze. The floors were paved with glass mosaic, the windows and door frames were made of bronze, and many of the decorations were priceless. The Romans made ball bearings out of lead and they probably used the ball bearings on the Nemi ships to make the statues of the gods rotate or to move the windlasses.
The flat bottomed Nemi barges were not self propelled. Instead, they were attached to the shore by chains and bridges stretching across the water so people and commerce could travel back and forth. The two largest ships were about 250 feet long and 70 feet wide, nearly covering small Lake Nemi.
These floating palaces were attached to the shore by chains, and bridges were built across the water to link with the ships. According to some historical accounts, Caligula’s ships were the scenes of orgies, murder, cruelty, music, and sport and he supposedly spent much of his inheritance from his Uncle Tiberius to create his Nemi Ship retreat.
Many people concluded that the Nemi Ships were pleasure barges, but Pliny the Younger disagreed. He said that since Lake Nemi was sacred, Roman law prohibited ships from sailing on it. Pliny argued that Caligula had received a religious exemption for his ships. Most Romans didn’t oppose Caligula building his ships on Lake Nemi. The citizens of Rome, many Roman soldiers, and visitors from the provinces and conquered lands come to admire Caligula’s Nemi ships.
Caligula Dedicated the Largest Nemi Barge to Moon Goddess Diana
Caligula dedicated the largest ship he had built to the moon Goddess Diana. The largest ship resembled one of his palaces transported to water and it featured a temple honoring Diana. Marble mosaic floors of many colors, inlaid ivory on the walls, heating and plumbing and baths were featured throughout both ships. The water flowed through pipes etched with Caligula’s name. Bronze sculptures were part of the decorations.
Some accounts say that Caligula took the sacred Lake Nemi which was also called “the mirror of Diana,” and the Goddess Diana more seriously than he did his throne and its riches. The Temple of Diana shimmered in a grove of oak trees on Lake Nemi’s shores, and every time the moon shone in its fullest splendor, Caligula. stretched out his arms to Diana and implored her to come to him.
The first Nemi Ship measured 350 feet in length and 60 feet in width and the smaller measured 179 feet long and 26 feet wide. The emperor used the second ship, nearly as large but not so ornate, to ferry his guests to the first ship. One was oared galley and the other a sailing vessel.
The Senate and Praetorian Guard Assassinated Caligula and Sunk His Barges
Caligula had no suspicions that officers of the Praetorian Guard and members of the Roman Senate and of the imperial court were conspiring to assassinate him. Although they successfully assassinated Caligula on January 21, 41 AD., the assassins were unsuccessful in their goal of restoring the Roman Republic. On the same day of Caligula’s assassination, the Praetorian Guard declared Caligula’s Uncle Claudius emperor to succeed Caligula.
Some surviving accounts of Caligula’s reign describe him as a noble and moderate ruler for the first two years of his rule, and then they focus on his cruelty, extravagance, and sexual perversity. Other sources say that during his reign, Caligula worked to increase the emperor’s authority and Rome annexed the Kingdom of Mauretania and converted it into a province during his reign. He directed a major part of his attention to construction projects, including luxurious homes for himself and two new aqueducts in Rome. Although the nature and extent of Caligula’s involvement with the Nemi ships are not sharply defined, it is clear that he was involved with them in some capacity. A lead pipe found on one of the wrecks is inscribed, “Property of Gaius Caesar Augustus Germanicus.” The dates on numerous tiles found on the wrecks of the Nemi ships also imply his involvement.
After Caligula's assassination, the Roman Senate and the Praetorian Gurad attempted to destroy everything connected with him, including his barges which they pillaged and sank. Fishermen handed down memories of Caligula's palatial Nemi ships to their descendants, someswearing that they could see the shadowy outlines of the ships in the waters of Lake Nemi. The ships were actually buried in the mud 200 yards distant from each other in five fathoms of water; one 150 feet from the bank and the other 250 feet from the bank. Legends of Caligula's sunken Nemi Ships filled with fabulous treasures reflected through generations of Lake Nemi citizens like images of the ships themselves.
The Nemi Barges in the Middle Ages
For centuries local fisherman considered Caligula’s sunken barges local landmarks in Lake Nemi, and some explored the wrecks and took small treasures from them, but wasn’t until the Middle Ages that anyone tried to explore and raise Caligula’s legendary ships.
In 1446, Cardinal Prospero Colonna an Italian humanist and renowned engineer Leon Battista Alberti followed the clues in the local legends about the Nemi barges and located them in about 60 feet of water. The wrecks lay too deep to be salvaged effectively, although Cardinal Colonna used pontoon bridges, windlasses, and inflated bladders. The salvage crews damaged the ships with the ropes and hooks they used to tear planks from them. The only thing Leon Alberti discovered about the wrecks was that they were made of cedar wood and they were covered with lead sheathing.
Nearly a century later, in 1535, Francesco de Marchi of Bologna, a great military engineer and the inventor of the modern sysem of fortifications, made another attempt to salvage Caligula’s Nemi ships. In his account of the operation which he wrote in Military Architecture, he said that he explored the wrecks in a diving bell that William of Lorraine invented. The diving bell was built of wooden planks calmped together with iron hoops and fitted it with glass windows in the front.
De Marchi took accurate measurements and obtained valuable information about the ships. After he examined the material that he had recovered from the wreckage of the ships, de Marchi concluded that the Romans had used mortise and tenon joints when they built the Nemi ships.
Nineteenth Century Efforts to Salvage the Nemi Barges
Over the next three centuries, fishermen and local divers kept the legend of Caligula’s ships and the hope of glittering treasure alive, but there were no official or government salvage efforts. Then in 1827, an effort to salvage the two ships broke off the prow of one of the vessels causing permanent damage. In September 1827, Archaeologist Annesio Fusconi built a floating platform to try to recover the wrecks and on September 10, he decided to use a diving bell called “Halley’s Bell,” which he supplemented with a modern pump to ensure air flow. In his memoris he provided a list of the items he had recovered, including two pieces of marble floor, marble pieces of various quality, enamels, mosaics, metal, bricks, clay pipes, and beams and wooden boards. He sent some of the items he recovered to the Vatican Museums and the rest were lost to history.
Eliseo Borghi Discovers Two Wrecks
Several decades later the House of Orsini and the Italian Ministry of Education joined with antiquarian researcher Eliseo Borghi to explore Lake Nemi for what they believed to be one wreck. On October 3, 1895, the professional divers that Borghi employed brought exciting discoveries to the surface, including pillars, bronze heads, parts of mosaics, and pottery.
They reported that the boats were made of cedar with a thick coating of pitch and covered with on the outside with a skin of sheet lead of great thickness fastened with copper nails and then a layer of cloth. The decks awere paved with glass mosaics of exquisite beauty. On November 18, 1895, much to their amazement, they discovered a second ship and recovered a Medusa’s head and several other items including beams in excellent condition.
The government purchased most of the recovered materials, but some of the gilded copper tiles, mosaic fragments, marble and lead pipes were confiscated and sold elsewhere and some were hidden away so they wouldn’t fall into the hands of the government. The Director General of the Department of Antiquity and Fine Art submitted a report to the government requesting that the recovery efforts be halted because of the “devastation of the two wrecks.”
A bitter controversy about what to do with the wrecks and the artifacts recovered from them played out in the newspapers and the government forbade the use of any methods that would injure the ships.
Borghi organized a company which offered shares for sale to raise money to drain the lake far enough so that he could reach the ships. Archaeologists who were consulted about the ships questioned the feasibility of Borghi’s scheme, stating that they feared that the two ships were too far decayed to hang together.
According to a Brooklyn Eagle story of August 10, 1902, an Italian Navy engineer, Comendatore Vittorio Malfatti and his crew, surveyed the wreck location between 1896 and 1905. They surveyed and charted the two Nemi ships and the lake bed to see if the two ships could be recovered intact. and Malfatti reported that the only workable way to do this was to partially drain the lake. He marked the outer wreck margins with buoys and recorded their positions on a chart of the lake. Malfatti believed that the ships were too fragile to be lifted, so he proposed that “if the ships could not be raised to the surface of the lake, then the surface of the lake should be lowered to the ships.”
Signor Malfatti’s report suggested building a tunnel or canal from the lake into which the water could be pumped. Almost three decades later Italian dictator Benito Mussolini, whose personality resembled Caligula’s if historical records are accurate, decided to settle the issue of recovering Caligula’s Nemi ships.
The Two Primary Nemi Ships are Recovered
The Fascist government of Benito Mussolini worked to recover Caligula’s ships for about five years – from October 1928 to October 1932. Mussolini ordered antiquarian Guido Ucelli, the Italian Navy, engineers of Civil Engineers, industry, private individuals and archaeologists to drain Lake Nemi. The local people and archaeologists knew of an ancient Roman underground tunnel that connected the lake to farms outside the crater and they connected it to a floating pumping platform. Using powerful pumps and water scooping machines, the workers lowered the level of the lake and by June 10, 1931, they had recovered the first ship and the second had been exposed. A London Times story reported that everyone on the site cheered as the waters receded to reveal the first Nemi ship. After nearly 1,900 years at the bottom of Lake Nemi, the ships again rode the waves.
With all of the water removed, the level of Lake Nemi had dropped 66 feet by August 21, 1931, and a mud shower occurred as a result of the sinking of the lake floor. Work stopped while the government and the archaeologists debated the future of the project, and Lake Nemi began refilling. The second ship had already partially dried out and resubmerging caused a great deal of damage to it. The Italian Minister of Public Works ordered the ship project and all of the research related to it to be abandoned on November 10, 1931.
The Navy Ministry which had participated in the original recovery petitioned the Italian Prime Minister to resume the Lake Nemi ship project on February 19, 1932, and the government granted them permission along with the Ministry of Education to resume the project. Pumping the waters of Lake Nemi resumed on March 28, 1932, and the second ship was recovered in October 1932.
The Nemi Ships and Their Artifacts
The hulls of the Nemi ships and their contents were recovered as well as items scattered around the ships, including bronze and marble ornaments, tiles and utensils. Scholars discovered that both ships had been sheathed in three layers of lead sheeting and paint and tarred wool protected their topsides. Rowers manning 37 foot long quarter oars steered the ships, with the larger ship using a total of four oars, two off each quarter and two from the shoulders.
Working inside a hastily constructed frame building, teams of historians and archaeologists began their scholarly studies of the artifacts found on both ships. The recovering of the Nemi ships settled a prolonged and sometimes contentious scholarly argument. Before the ships were recovered, many scholars scoffed at the idea that the Romans were capable of building large enough ships to carry grain, despite ancient sources that said they had built such ships. The size of the Nemi Ships proved that the ancient sources were correct.
Over the centuries, scholars have also debated whether or not the lead bars found on the bottom of the Mediterranean Sea were anchor stocks. The Nemi ships were built during the transition between wooden and iron anchors and they were the first Romans ships found with intact anchors. The Nemi ships confirmed that the lead bars were anchor stocks.
Both of Caligula’s Nemi ships contained several hand operated bilge pumps working like modern bucket dredges, the oldest example of this type of pump ever found. Piston pumps on the two Nemi ships supplied hot and cold running water through lead pipes. The Romans used the hot water for baths and the cold water for fountains and drinking water. This piston pump technology later was lost to history and not rediscovered until the Middle Ages.
The Italian government built a museum called the Lake Nemi Museum over both ships in 1935 and it opened in January 1936.
The Nemi Ships Burn During World War II
Benito Mussolini threw his personal fortunes and Italy’s fate behind the Germans in World War II, and by 1944 the tides of war were turning in favor of the Allies. The Italians deposed Mussolini from his dictatorship of the country and Italy surrendered and moved to the Allied side. The Allied forces advanced north into Italy, striving to hold a line from Monte Cassino eastward through the Alban Hills near Lake Nemi. On May 31, 1944, Allied planes and artillery units bombarded a German anti-aircraft battery stationed near the Lake Nemi Museum.
Some shells struck the Lake Nemi Museum, but they didn’t cause much damage. Then a few hours later, smoke arose from the Museum and soon the two ships were burnt to ashes although the museum’s concrete structure suffered little damage. Later in 1944, Italians filed an official report in Rome, charging that German soldiers had burned the Nemi Ships. German newspaper stories blamed the fire on American artillery fire.
The Museum keepers later swore that the Germans had ordered them away. Later, historical consensus said that the retreating Germans set fire to the two ships as an act of spite. During the German retreat, soldiers burned 80,000 books and manuscripts of the Royal Society of Naples as well as the two Nemi Ships. Like the Emperor Caligula, Italian dictator Mussolini died violently at the hands of his countrymen on April 28, 1945.
The Lake Nemi Musem Survives
The Lake Nemi Museum was restored and reopened in 1953. Photographs, drawings from the Italian Navy survey, and drawings of archaeologist G. Gatti also survived the fire, allowing artists and architects to make reconstructions of the two ships. The spaces that once held the two immense Nemi Ships are now filled by one-fifth scale models built in the naval dockyard near Naples, and bronzes and other artifacts that survived the fire. Outside the Lake Nemi Museum, a life-size reconstruction of the sailing ship’s hull is displayed.
In 1995, the Association Dianae Lacus – Lake of Diana-founded to preserve the culture and history of the Nemi Lake area, originated Project Diana with the goal of building a full size replica of the first Nemi ship. The group planned to build the replica to deck level only and moor it on Lake Nemi in front of the Lake Nemi Museum.
The Nemi town council voted to finance the building of the forward section of the first Nemi Ship in July 1998, and the Torre del Greco shipyards completed it in 2001. The finished section was transported to the Lake Nemi Museum to await the next step in the project, dubbed Project Diana, which was estimated to cost $10.7 million dollars or 7.2 million Euros. When Caligula had the Nemi Ships built, he established a lavish, historic, and trailblazing legacy for the ships, and their story and their survival have fulfilled that legacy.
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Ucelli, Guido. Le Navi De Nemi, 1983.