The name of this lake and of the village on its margin, is derived from the great grove of Diana (Nemus Dianæ) whose temple probably stood on the site of the present village of Nemi. The wooded cliffs which surround the crater here are steep and descend immediately into the water, except on the side near Genzano, where they slope magnificently and are planted with vines. Their average height is 300 feet. In the Latin poets frequent mention is made of this lake as one of the principal ornaments of the neighbourhood of Rome, and in connection with the widely celebrated temple of Diana. Hence it was called Speculum Dianæ, lacus Triviæ and Stagnum Dianæ.
Whether the name Lacus Aricinus also belonged to this lake is doubtful, for Pliny speaks of a lake which formerly occupied the valley of Ariccia, and the water in this valley was certainly called Lacus Aricinus in the middle ages.
The water of the lake is supplied partially at least from a small spring near the road from Genzano to Nemi, and also from the copious stream which turns the mills of the village of Nemi. The latter is probably alluded to by Strabo when he says that the sources whence the lake is filled are visible, and are near the temple of Diana.
Nibby gives the following account of the Lake of Nemi, and of the investigations carried on in his time for the purpose of discovering the real nature of the curious wooden fabrics said to have been found at the bottom of the lake:
“The situation of Nemi is picturesque, and the view from it of the crater, and of the lake, which resembles an enormous mirror spread below, is magnificent. But beyond the historical reminiscences of the Temple of Diana, it presents nothing worth particular mention. The baronial castle near it has all the appearance of a feudal fortress. It was built by the famous Colonna family, once the lords of the estate, who also built the round tower or keep which surmounts it. By ascending the side of the mountain which rises above it, a splendid panoramic view of the coast of Latium and of the adjacent Rutulian and Volscian territory may be enjoyed. The eye ranges along the whole coast line of the Tyrrhenian Sea, from the Circæan promontory to the mouths of the Tiber, and the situations of Astura, Antium, Ardea, Lavinium, Laurentum, Ostia and Porto are clearly distinguishable, together with many other points.”
“The crater is surrounded in parts by rocks of the hardest basaltic lava, in others by conglomerated cinders and scoriæ, and in some places by banks of tufa. Its circumference is about five miles; and the level of the water is higher than that of the Alban Lake. The story of the ship discovered at the bottom of this lake and said by some authors to have belonged to the time of Tiberius, by others to that of Trajan, is well known. Biondo, Leon Battista Alberti, and particularly Francesco Marchi a celebrated architect and military engineer of the sixteenth century, who went down into the lake himself, have spoken of it.[141] Fresh investigations have been carried on of late, at which I was present, and saw and examined everything which was brought to the surface, and inquired of those who went down what they saw there. I consider myself in a position to assert that the pretended ship was nothing more than the wooden piles and timbers used in the foundations of a building. The beams are of fir and larch, and are joined by metal nails of various sizes. The pavement, or at least the lowest stratum, of the remains is formed of large tiles placed upon a kind of grating of iron, on which the name CAISAR, in ancient letters, is marked. Some of these tiles and nails and gratings are now kept in the Vatican Library.
“The name Caisar seems to explain the history of the building, for Suetonius in his ‘Life of Julius Cæsar,’ as an illustration of Julius Cæsar’s extravagance, asserts that after having built a villa on the lake of Nemi at an enormous expense, he had the whole destroyed because it did not quite suit his taste. It is my belief that the pretended ship was nothing else than the piles and wooden framework upon which this villa was supported, and that after the upper part was destroyed the foundations under the water still remained, partly covered by the fragments of the demolished building above.”[142]
The mention of paving tiles, marbles, and leaden pipes as among the objects raised from the bottom of the lake, renders the notion that they belonged to a ship improbable, and Nibby’s conjecture that a Roman villa, partly built out into the water, stood here, seems much more likely, though his application of the passage of Suetonius is very doubtful.
Cav. Rosa, who examined the neighbourhood of Nemi and Genzano with a special view to the solution of the question of the site of the Temple of Artemis, has given a careful account both of the ruins under Genzano and those to the west of Nemi. The former he pronounces undoubtedly to belong to a villa, the latter he thinks belonged to a temple with a large court in front, and an ancient road leading to it from the western side of the lake. These ruins are just above the lower road leading from the Capuccini convent at Genzano to Nemi, at the point where a cross road leads to the left and joins the higher road to Nemi, not far from the place called le Mole.[143] Genzano is a town of mediæval origin.
(B) THE VIA LATINA AND TUSCULUM.