1911 Encyclopædia Britannica/Albanus Lacus

ALBANUS LACUS (mod. Lago di Albano), a lake about 12 m. S.E. of Rome. It is generally considered to have been formed by a volcanic explosion at the margin of the great crater of the Albanus Mons; it has the shape of a crater, the banks of which are over 400 ft. in height from the water-level, while the water is as much as 560 ft. deep in the S. portion. It is fed by subterranean springs. According to the legend, the emissarium (outlet) which still drains it was made in 398–397 B.C., the Delphic oracle having declared that Veii could only be taken when the waters of the lake reached the sea. It is over a mile in length, hewn in the rock, and about 6 ft. high and 4 ft. broad; it has vertical shafts at intervals, and a sluice chamber at its egress from the lake. In the time of Domitian the whole lake belonged to the imperial domain. (See Alba Longa.)