(anc. geog.), a lake of Italy in the country of the Marfi. Now Lago di Celano, from a cognominal citadel, lying in the south of the Abruzzo Ultra, in the kingdom of Naples, near the Apennine. This lake was under the protection of a god of the same denomination, whose temple stood on its banks. According to the testimony of ancient authors, it was subject to extraordinary risings and decreasings. The actual circumference is 47 miles; the breadth in the widest part is 10, in the narrowest 4; its depth 12 feet upon an average. But all these have varied prodigiously. Two miles up the plain, behind Avezzano, the fragments of boats, shells, and other marks of its ancient extent, have been casually discovered: and, on the contrary, there are people who remember when it did not flow nearer than within two miles of Avezzano. An immense tract of excellent land is lost at every increase of its level. All round this noble piece of water rises a circle of grand mountains, some of them the highest in Italy, if we except the Alps, and many of them covered with snow; and at the foot of them are numerous villages, with rich and well cultivated farms. The environs of the lake, Mr Swinburn describes as all well inclosed, and the sides of the hills as covered with fine woods; its waters abound with fish of various kinds, and thither repair at stated seasons innumerable flights of wild-fowl. As the swelling of the lake was attended with incredible damage, the Marfi had often petitioned the senate to drain it: Julius Caesar would have attempted it, had he lived longer. His successors were adverse to the project; till Claudius, who delighted in expensive difficult enterprises, undertook it. During the space of 11 years he employed 30,000 men in digging a passage through the mountain; and when every thing was ready for letting off the water, exhibited a superb naval spectacle on the lake. A great number of condemned criminals were obliged to act the parts of Rhodesians and Sicilians in separate fleets, to engage in earnest, and to destroy one another for the entertainment of the court and the multitude of spectators that covered the hills: A line of well-armed vessels and rafts loaded with soldiers surrounded the scene of action, in order to prevent any of the wretches from escaping; but it was with great difficulty and many threats that they could be brought to an engagement. When this savage diversion was ended, the operations for opening the emissary or outlet commenced, and the emperor was very near being swept away and drowned by the sudden rushing of the waters towards his tent. However, either through the ignorance or negligence of the engineers, the work did not answer as was expected, and Claudius did not live long enough to have the faults amended: Nero abandoned the scheme through envy. Hadrian is said to have let off the waters of the Fucinus; but none now escape except through hidden channels formed by nature, which are probably subject to be obstructed, and thus occasion a superabundance of water in the lake, till some unknown cause removes the obstructions and again gives free passage.

Sir William Hamilton, who visited the Fucinus in 1785, says, "it is the most beautiful lake he ever saw, and would be complete if the neighbouring mountains were better wooded." It furnishes abundance of fish, though not of the best quality. There are a few large trout, but mostly tench, barbel, and dace. In the shallow water on the borders of the lake, he saw thousands of water-snakes pursuing, and preying upon a little kind of fish like our thornbacks, but much better armed; though their defensive weapons seemed to avail them but little against such ravenous foes. Claudius's emissary he describes as still entire, though filled up with earth and rubbish in many parts. He went into it with torches as far as he could. It is a covered underground canal three miles long, and part of it cut through a hard rock; and other parts supported by mason work, with wells to give light. Hadrian is said to have let off the waters of the lake; and our author is of opinion, that if the canal were cleared and repaired, it would still answer that purpose, and thereby restore a great deal of rich land fit for cultivation.