By  Cormac F. Lowth.
Hull 1 from Lake Nemi

A hull on Lake Nemi

There is a small lake called Nemi in the Alban Hills, about 30 kilometers southeast of Rome.  Between 1927 and 1933, two enormous wooden ships, which once belonged to the Emperor Caligula, and had lain on the bottom of the Lake for over nineteen hundred years, were salvaged in what was perhaps the greatest underwater archaeological recovery ever accomplished.  Not until the raising of the VASA in Sweden, and the MARY ROSE in England, was anything remotely comparable to be achieved. One of the most fascinating aspects of the whole affair is the fact that knowledge of the two huge vessels being in the lake had never been lost throughout the ages, from the reign of Caligula, to the twentieth century.  There were several attempts at salvage carried out at various times, most of which resulted in degradation of the wrecks and plundering of artefacts.

Lake Nemi is a place of great Scenic beauty. It is formed by the crater of an old volcano and the name is derived from the Latin word for a grove.  It lies at about three hundred metres above sea level and the maximum depth in the lake is about thirty- four metres. Throughout history, various deities have been venerated there.  The area is principally associated with the goddess Diana and the lake was known in antiquity as the Speculum Dianae or ‘The Mirror Of Diana’   The remains of a temple dedicated to Diana have been excavated near the lake shore.  Today, the lake and surroundings still have a magical quality and there is an abundance of woods and wild strawberries growing around its banks.  The Alban hills region is reputed to be the birthplace of Romulus and Remus, the mythical founders of Rome.  The area is a popular tourist venue and is now, as in past times, a place of resort for many of the inhabitants of Rome.  The ruins of grand villas are to be seen where Emperors and later wealthy Romans once enjoyed the enchanting ambience of the lake.  Julius Caesar and his successor Augustus are said to have built large palaces there, to which they retired in summer.  Nemi has always attracted writers, poets and artists.  Byron wrote of ...Nemi, navelled in the woody hills… Of the many depictions of the lake by artists, including Turner, the scene painted by Joseph Wright of Derby in 1790 is one of the most beautiful.

A painting of Lake Nemmi by Joseph Wright

A painting of Lake Nemmi by Joseph Wright

The emperor Caligula had a very brief reign.  He ruled from 37A.D. to 41A.D. for a period of three years and ten months.  He is generally depicted by historians as a cruel megalomaniac who was noted for many excesses, not the least of which was his ability to squander, in a year, the entire resources of the Imperial treasury that had been built up by his predecessor Tiberius, on extravagant but useless schemes.  If so, the sheer scale of the two gigantic ships that he had built to float upon so small a lake as Nemi, would seem to be in keeping with the descriptions given of his behaviour.  Lake Nemi covers about 1.7 square kilometres. Its average width is about one kilometre. The two vessels, which were designated in modern times as Prima Nave and Seconda Nave, (First Ship and Second Ship), had dimensions of 67m x 19m and 71m x 24m respectively.  Placed together, they would have taken up much of the area of a football pitch.  While there can be little doubt that the ships were built at the capricious whim of a spendthrift despot, their intended purpose and eventual use has long been the subject of debate by scholars and historians.  It is generally agreed that one of the ships was designed to be a floating temple to Diana, or others of the many deities that were then in vogue, while the other vessel may have been used as a palace afloat for the Emperor and his court where he undoubtedly would have indulged in many of the depravities that are attributed to him.  It is apparent that both ships were originally built using the standard sea-going shipbuilding techniques and materials of the day and that they were fitted out to an extremely high standard of luxury and decoration.  Caligula’s brief reign came to an abrupt end when he was assassinated by members of the Praetorian Guard, who were sickened by his depraved behaviour and reckless expenditure, in A.D. 41.  He was twenty-eight years of age.  When they were finally brought to dry land, having lain on the lake bed for almost two millennia, and having endured the rigours of many salvage attempts, Caligula’s ships were to have an equally tragic and violent end as that of their instigator, but thankfully, not before they had yielded up much of their unique archaeological information.

Nothing is known of the circumstances in which the ships sank.  There is speculation that they simply floated on the lake until they leaked and became waterlogged.  Other commentators have conjectured that Caligula’s successor, Claudius, a more benign and prudent ruler, may have had them sunk to help obliterate the memory of his decadent predecessor. There were descriptions of the ships written by Roman historians.  Seutonius describes two ships built by Caligula with  …Ten banks of oars...the poops of which blazed with jewels...they were filled with ample baths, galleries, and saloons, and supplied with a great variety of vines and fruit trees. It is reasonable to suppose that the Nemi ships were equipped to a comparable standard.  The water in Lake Nemi can be quite clear at times and it has been stated that the outline of one of the ships could be seen at times from the surface.  The First Ship lay at depths from five to fifteen metres while the Second Ship lay at twenty metres. Throughout the dark ages the knowledge of the ships remained in the local consciousness having been passed down from one generation to the next.  In mediaeval times the lake and surrounding district were owned by members of the Borgia dynasty.  During the Renaissance, in 1446, the first serious attempt at salvaging the wrecks was instigated by the Lord of Nemi who was a scholar of ancient Roman history, Cardinal Prospero Colonna.

The Cardinal had studied the ancient texts and was aware of the local folklore concerning the ships.  Fishermen showed him pieces of worked timber that had come up in their nets. He engaged a famous architect, Leon Battista Alberti, to undertake the attempt.  Alberti was rightly regarded as a genius in the mould of da Vinci.  He constructed a huge raft from empty barrels and beams, and around this floating platform he mounted winches with hawsers and grappling hooks.  Despite all of his efforts, the ships would not be pulled from the mud of the bottom and the hawsers frequently broke, however, he succeeded in tearing away a few portions of the hull, which revealed that the bottoms were sheathed with lead and that the woodwork was of a high quality. A contemporary account describes…

There were brought from Genoa some sailors who swam like fishes, and who, diving down to the bottom of the lake, were enabled to ascertain the size of the ships...and attached to them all the aforesaid iron hooks.  One of the hooks being attached to the prow, there broke off and came away only a part, to examine the construction of which, there came from Rome, all the brightest intellects of the Roman Court.

This was to set the pattern for many future attempts until the ships were finally taken from the water in the twentieth century.  The motivating factor in most subsequent attempts at salvage before the final success was not of an archaeological nature but lay in the possibility of finding treasure, and valuable antiquities, for profit.

Although there was some free diving carried out on the wrecks over the centuries, the first successful diving attempt using an apparatus was carried out in 1535 by Francesco de Marchi.  He was a military engineer who designed fortifications in addition to being a prolific author who described in great detail his adventures beneath the surface of Lake Nemi.  He was sometimes given to flights of exaggeration and rather fanciful accounts of what he had seen below the surface, particularly in his descriptions of fish.  He improved upon a type of helmet that had recently been designed by Guillam de Lorena.  This was a weighted boxlike wooden structure with glass windows and it simply sat on De Marchi’s  shoulders and reached down to his waist.  He seems to have contrived a method of replenishing the air in the device although his writings are vague on this point and really give no clue as to how he accomplished this.   Nevertheless, he was able to descend for fairly long periods and he made crude attempts at measuring the ships.  His measurements were hugely inaccurate as he described the vessels as being much larger than they actually were.  It is highly probable that the natural magnification experienced under water was added to by the distortions of the crude glass panels in the helmet. He humorously described the annoyance of having small fish nibble at his ‘extremities’ when he was underwater with no trousers on.  He retrieved some small artefacts including portions of lead piping.  De Marchi now tried to recover the wrecks using the same method as Alberti but he had no success other than to tear off more pieces of the ship including some lead sheathing from the ship’s bottom.  De Marchi’s dives are regarded as the first to be undertaken using a helmet apparatus.

In most of the intervening periods between major salvage efforts, the wrecks were never to remain undisturbed.   Fishermen constantly used grappling hooks and pulled up various pieces, which they sold to visitors, particularly in the eighteenth and nineteenth centuries when the ‘Grand Tour’ for wealthy European gentlemen took in places of antiquity in Italy.

The next recorded major attempt at recovery on the two ships took place in 1827.  An Italian knight, Annesio Fusconi used a large diving bell similar to the type that had been designed by Edmond Halley, the British Astronomer Royal, and the man for whom the comet is named.  Halley first descended in a diving bell of his own design in 1690 in the River Thames.  Fresh air was sent down from the surface in barrels to replenish the spent air in the bell.  Fusconi’s bell was slung from the middle of a large floating platform.  He had as a prime objective the recovery of archaeological objects for sale to the gentry and nobility and to foreign visitors.  This was still well within the era of great collectors of all things old who styled themselves as ‘Antiquarians’.  He had a regular audience of these gentlemen aboard the diving platform.  He and a team of workmen recovered many artefacts.  The finds included bricks, and marble paving- stones, bronze, copper, and lead artefacts and a great deal of timber beams.   He had all of the wood made into items such as walking sticks and boxes and he found a ready market for everything recovered among the waiting gentry.

Fusconi tried the same methods as the previous salvers to attempt to lift the wrecks but again, some of the cables snapped when the weight came on the winches and he merely ripped more parts from the wrecks.  His activities ceased towards the end of the year and he departed, whereupon, all of the barrels that made up the raft were purloined by the local peasantry to hold the wine made from an exceptional harvest of grapes that year.  When he returned in the following Spring, he found he was unable to continue without his raft and he abandoned the project. Some of the artefacts recovered were acquired by museums but most disappeared into private collections.

In 1895 a dealer in antiquities named Eliseo Borghi began diving operations in Lake Nemi.  He had been involved in private excavations around the site of the Temple of Diana on the shore of the lake in cooperation with Count Orsini, the owner of the Nemi region, where marble statuary and friezes were recovered and sold on the open market.  Many were bought by museums and some of these are in the British Museum.  With authorisation from Count Orsini and with the knowledge of the Ministry of Education, Borghi employed divers using modern standard dress and they began to systematically penetrate the wreck-sites in a way that had never been possible before.  Many beautiful artefacts now began to emerge including some that were to become iconic images in connection with the ships of Lake Nemi.  These were cast bronze heads of animals, with rings through the mouths that included foxes, wolves, lions, and panthers, with large square sockets, that had once adorned the ends of beams on the ships.  A beautiful bronze head of Medusa that was recovered once fulfilled the same function.  There were sections of coloured mosaics and more lion-head cappings for rudder shafts.  Borghi placed all of his finds in his private museum and offered the collection for sale to the Government.  He had also retrieved timbers from the wreck that were left in the open and allowed to deteriorate. An enlightened Director General of Antiquities and Fine Art, Signor Barnebei, now intervened and put an embargo on further diving by Borghi, while he claimed all of the artefacts that had been found for the National Museum.  While both Fusconi and Borghi catalogued and described many of their finds, no contextual referencing was included.

This effectively put an end to all private depredations upon the wrecks and the government now ordered a survey to be carried out of the entire site.  The man charged with this task was an Italian Naval Engineer, Commendatore Vittorio Malfatti.  Between 1896 and 1905, Malfatti and his team of naval divers accurately surveyed and charted the wrecks and the bed of the lake and compiled an extensive report on the condition of the ships, and a detailed plan as to how they could be raised from the lakebed. He began by delineating the outer margins of the wrecks with buoys and marking these positions on the chart of the lake.  In the belief that the ships were too fragile to stand lifting, Malfatti was the first to propound the notion 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.

The periods before, during, and after the First World War were times of great political upheaval in Italy, and despite the general enthusiasm for the idea of recovering the ships, there was no further activity for the next twenty years.  The Fascist Government under Benito Mussolini had come to power in 1922 and four years later, in 1926, a Committee was formed to study afresh the possibilities of lowering the lake and raising the ships.  Mussolini was wholeheartedly enthusiastic about the project and gave his full cooperation, which he outlined in a ‘passionate and vibrant’ speech in 1927.  It has been said that he saw his Government under the Fascists as a regeneration of the old Roman Empire and he embraced anything connected to it.  The man appointed in overall charge of the project was Signor Guido Ucelli who later published a fascinating book on the subject in 1940.

When the decision was made to begin the work, it was discovered that an existing drainage tunnel from the lake was adequate to drain the water from the pumps.  This was known as an ‘emissario’ and it had been dug during ancient times to keep the waters of the lake at a constant level to prevent flooding. There was a suggestion to siphon the water from the lake but this was dismissed as unworkable.  The tunnel meandered for 1.6 kilometres through the hillside to the Arricia Valley from where the water went by drainage ditches to the sea.  Much work was needed to refurbish the emissario but despite some misgivings, it proved perfectly capable of handling the flow.  Four giant pumps on the lake shore with armoured flexible pipelines from the lake to the emissario were provided free of charge by the engineering firm ‘Costrutzioni Meccaniche Riva Milano’ and on October 20th 1928, the pumps were switched on by Signor Mussolini and the work of draining the lake began. Many more private firms were to follow suit by providing services at no cost in what was regarded as a great patriotic gesture.

As the level of the lake began to recede it became necessary to mount the pumps on a floating platform in the water. Pumping went ahead around the clock but it was not until the end of March, 1929, that the top of the first ship began to appear.  One of the first objects recovered was a 12-metre long circular rudder shaft, capped with a Bronze lion’s head.   The water in the lake did not drop sufficiently to uncover the ship completely until the following October 1931, when the level had dropped by more than fifteen metres. The mud had been cleared away from the hull as the level had dropped and immediately the recovery plan swung into action.  Prefabricated sections of a giant cradle were assembled around the hull and track-ways were laid at an incline up to a prepared site on the lakeside.  The devastation caused by previous attempts at lifting was all too apparent from the time the ship became visible.  Practically all of the original upper-works had been torn off and what remained lay in a jumble inside the hull with a multitude of other artefacts.  It was concluded that there had been extensive buildings aboard judging by the sheer amount of masonry, marble and various types of columns that were found.  Panelled joinery was discovered with small elaborate hinges and catches.

Hordes of people of many disciplines worked feverishly to examine the wreck and to prevent the hull from drying out and disintegrating. Storehouses were built on the shore to house and conserve all of the loose material and small objects.  Circular platforms with roller bearings were discovered and it was thought they might have been for mounting statuary.  Tons of bricks with the makers name incised, marble and mosaics were found.  A huge amount of concrete was removed, in some of which were embedded vitreous tiles. Bronzes, terra cotta and lead pipes and scuppers, and a 400mm wide tapered bronze stopcock were among the items recovered. Some of the mosaics had the exact colour combination of the modern green, white, and red, Italian flag.  For a brief time, members of the public were allowed to troop by on catwalks to observe the work. Signor Malfatti, who had conceived the plan for recovery, had the task of showing visiting archaeologists around.  The hull was covered with fabric, which was kept continually wet to prevent drying, and an aircraft hanger was constructed over the ship, compliments of the Minister for Aeronautics.

By now the second ship was visible just below the water but the pumping had been stopped.  The Committee were unsure if the expense and effort of raising the second ship could be justified, however, both the leader of the Government and the firms that were providing the pumping and mechanical services gave their assurances of full support.  The Navy Ministry had been helpful from the start and further help was promised. The pumps were restarted and, by the end of 1932, the second great ship had been pulled clear of the lake and conservation work had begun. During this renewed pumping process there was a huge mudslide, caused by the depleted water level, which partially slewed and inundated the ship.  It did not prove to be a great problem and there was no recurrence before the ship was raised.

The Archaeologists were faced with a huge problem in conserving the ships.  Nothing on this scale had ever been tried before and there were few previous examples to  learn from.  Intact Viking ships that had been found in burial mounds had been conserved in Scandanavia, notably at Gokstad and Oseberg.  The principal materials used were alum and linseed oil.  These methods were looked at but it was decided to treat the Nemi ships initially with wood tar.  Polyethylene glycol had not yet arrived in the world of conservation. A site was prepared for a permanent museum to house the ships and this was built using cast concrete trusses, a method much in favour in Italy at the time.  There were several other interesting finds in the lake including a small boat about ten metres long with a pointed bow and a square stern.  This was loaded with stones and it is thought to have been contemporaneous with the ships.  A huge wooden anchor with a lead stock and flukes tipped with iron was found with a large rope cable still attached.  Another anchor of Iron resembling an Admiralty pattern anchor, which was cladded completely with timber, was found, also with a rope cable.   The wooden anchor with the lead stock was the first of its kind ever to have been found intact and it laid to rest forever the arguments that had raged about the manner in which lead stocks were used on ancient anchors.  Many lead stocks had been found underwater in the past, particularly by sponge divers in the Mediterranean, but no trace of the timber parts were ever found.  A large collection of grappling irons, that evidently had been lost during previous salvage attempts, were found in both hulls

The construction of the ships proved to be of great interest and the hulls immediately began to answer many age-old questions about the construction of Roman vessels.  It was discovered that there were projecting platforms built around heavy cantilevered beams on either side where the rowers would have sat.  The ends of these beams had all been adorned with the bronze animal heads that had been found.  The ship’s bottoms and keels were completely sheathed in lead that was nailed on with flat-headed bronze nails over a tarred woollen fabric. The planking was fashioned in accordance with the known Roman methods of hull-first carvel construction with mortises, and loose tendons with pegs, let into the edges. The types of wood used in the building of the ships proved to be cedar, pine, oak, and larch.  Once ashore and housed in the new museum the conservation of the ships and the recovered objects went ahead with great efficiency and throughout the 1930s they were examined measured and studied minutely.  The Museum developed into an extremely popular venue for Italians and visitors alike, however, tragedy was looming on the horizon.

Italy made the disastrous decision to enter the Second World War on the side of the Germans.  By 1944 the tide of war had begun to turn and the Allies had invaded, first Sicily, and later the Italian mainland.  Mussolini had been deposed from government and Italy had capitulated and had gone over to the side of the Allies.  The German army were fighting a rearguard action, as the Allied forces advanced northward, and they were endeavouring to hold a line from Monte Cassino eastwards through the Alban Hills.  They were proving almost impossible to dislodge despite heavy aerial bombing.  On May 31st a German anti aircraft battery stationed near the Museum was undergoing bombardment from Allied planes and artillery units.  The Museum was struck by some shells but no great damage was caused.  The action ceased at about 20.00 and the Germans moved off shortly after.  At about 22.00, smoke was seen coming from the Museum and in a short while the two ships were completely burnt to ashes.  The Museum keepers later deposed that they had been ordered away by the Germans.  Incredibly, the structure of the museum, being concrete, suffered little damage. Despite later denials, it is generally acknowledged that the retreating Germans set fire to the two ships as an act of venomous spite.  Mussolini, like his Emperor predecessor Caligula, died a violent death at the hands of his fellow countrymen, on April 28th 1945.

Today, the Lake Nemi Museum still exists in the same building.  It was restored and reopened in 1953. The building now has a hollow ring to it and the spaces once taken up by the two mighty ships are now occupied by one-fifth scale models that were built in the naval dockyard near Naples, and various artefacts that had escaped destruction.  Fortunately there are comprehensive lines taken from the ships in existence.  There is presently an ongoing project to construct a full- sized replica of one of the ships.

Guido Ucelli’s magnificent book, Le Navi De Nemi, which contains an astonishing visual and written record of the recovery and conservation of the two ships, was written before the ships were destroyed and it has assumed an even greater significance as an enduring record of these lost treasures of Ancient Rome.  Had they survived they would have remained some of the greatest archaeological wonders of all time.