SARDO´UM or SARDO´NIUM MARE(τὸ Σαρδον πέλαγος, Strab., Pol., but τὸ Σαρδόνιον πέλαγος, Hdt. 1.166), was the name given by the ancients to the part of the Mediterranean sea adjoining the island of Sardinia on the W. and S. Like all similar appellations it was used with considerable vagueness and laxity; there being no natural limit to separate it from the other parts of the Mediterranean. Eratosthenes seems to have applied the name to the whole of the sea westward of Sardinia to the coast of Spain ( ap. Plin. 3.5. s. 10), so as to include the whole of what was termed by other authors the MARE HISPANUM or BALEARICUM;but this extension does not seem to have been generally adopted. It was, on the other hand, clearly distinguished from the Tyrrhenian sea, which lay to the E. of the two great islands of Sardinia and Corsica, between them and Italy, and from the Libyan sea (Mare Libycumn), from which it was separated by the kind of strait formed by the Lilybaean promontory of Sicily, and the opposite point (Cape Bon) on the coast of Africa. (Plb. 1.42; Strab. ii. pp. 105, 122; Agathem. 2.14; Dionys. Per. 82.) Ptolemy, however, gives the name of the Libyan sea to that immediately to the S. of Sardinia, restricting that of Sardoum Mare to the W., which is certainly opposed to the usage of the other geographers. (Ptol. 3.3.1.) Strabo speaks of the Sardinian sea as the deepest part of the Mediterranean; its greatest depth was said by Posidonius to be not less than 1000 fathoms. (Strab. ii. pp. 50, 54.) It is in fact quite unfathomable, and the above estimate, is obviously a mere guess.
[E.H.B]