Clanis

CLANIS or GLANIS(Κλάνις, Strab.; Γλάνις, App.: Chiana), a river of Etruria, flowing through the territory of Clusium, and falling into the Tiber about 14 miles below Tuder. It is mentioned by several ancient writers as one of the principal tributaries of the Tiber (Strab. 5. p. 235; Plin. Nat. 3.5. s. 9; Tac. Ann. 1.79; Sil. Ital.): but we learn from Tacitus that as early as A.D. 15, the project was formed of turning aside its waters into the Arnus. The Clanis is in fact the natural outlet that drains the remarkable valley now called the Val di Chiana, which extends for above 30 miles in length from N. to S., from the neighbourhood of Arezzoto beyond Chiusi, and is almost perfectly level, so that the waters which descend into it from the hills on both sides would flow indifferently in either direction. In ancient times they appear to have held their course entirely towards the S., so that Pliny considers the river as proceeding from Arretium, and calls it Glanis Arretinus:it formed, as it still does, a considerable lake near Clusium (Strab. 5. p. 226), now called the Lago di Chiusi, and had from thence a course of about 30 miles to the Tiber. But repeated inundations having rendered the Val di Chianamarshy and unhealthy, its waters are now carried off by artificial channels; some, as before, into the lake of Chiusi, others to the N. towards the Arno, which they join a few miles from Arezzo. The two arms thus formed are called the Chiana Toscanaand Chiana Romana. The latter falls into a stream called the Paglia, about 5 miles above its confluence with the Tiber. So slight is the difference of level, that it is even supposed that at one time a part of the waters of the Arnus itself quitted the main stream near Arretium, and flowed through the Val di Chianato join the Tiber. [ARNUS] It is, however, improbable that this was the case in historical times. (Fossombroni, Mem. sopra la Val di Chiana, 8vo. 1835; Rampoldi, Corogr. dell' Italia, vol. 1. p. 656.)
Appian mentions that in B.C. 82, a battle was fought between Sulla and Carbo, on the banks of the Clanis, near Clusium, in which the former was victorious ( B.C. 1.89).
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