Near Castelvecchio, atop the Apennine ridge separating the Valle del Diaterna from the Emilian plain, there has been from time immemorial a place called La Fossa di Catilina. The name already appears in Emanuele Repetti's Dizionario Geografico Fisico Storico della Toscana, which cites it as one of the characteristic topographic features of the area around Castelvecchio — a presence so deeply rooted in local memory that it survived for centuries in everyday speech.
The reference is to Lucius Sergius Catilina (Rome, 108 BC – Pistoia, 62 BC), a Roman general and politician known for the conspiracy that bears his name: an attempt to overthrow the Roman Republic, uncovered and exposed by Cicero in 63 BC. Forced to flee, Catiline took refuge in Etruria, where his lieutenant Gaius Manlius — perhaps a native of the area around Fiesole — was raising an army of rebels, Sullan veterans and common people weary of the abuses of the aristocracy. After Sulla's death the people of Fiesole decided to support the rebel Catiline, weary of the hardship that followed Roman domination. Great unrest shook the whole Mugello, Etruria and Fiesole in particular.
Catiline's army gathered in the mountains above Fiesole, but the arrival in Florence of Marcus Petreius' troops and, from the north, those of the consul Quintus Metellus caught the rebels in a vice, so that Catiline was forced to flee towards Pistoia with about a hundred loyal men. Crossing these places before the final battle, his troops left so strong a mark on collective memory that the area still bears his name.