, Ptol.; Θόρσος
, Paus.: Tirso
), the most considerable river of Sardinia, which still retains its ancient name almost unaltered.
It has its sources in the mountains in the NE. corner of the island, and flows into the Gulf of Oristano
on the W. coast, after a course of above 75 miles. About 20 miles from its mouth it flowed past Forum Trajani, the ruins of which are still visible at Fordungianus;
and about 36 miles higher up are the Bagni di Benetutti,
supposed to be the Aquae Lesitanae of Ptolemy. The Itineraries give a station “ad Caput Tyrsi” (itin. Ant.
p. 81), which was 0 M.P. from Olbia by a rugged mountain road: it must have been near the village of Beudusò.
(De la Marmora, Voy. en Sardaigne,
vol. ii. p. 445.) Pausanias tells us that in early times the Thyrsus was the boundary between the part of the island occupied by the Greeks and Trojans and that which still remained in the hands of the native barbarians. (Paus. 10.17.6