Arezzo was founded in pre-Etruscan in an area inhabited since prehistoric times, as evidenced by the discovery of stone tools and the so-called "Man Elm", dating back to the Paleolithic, which occurred near the hamlet dell'Olmo during excavation work a short tunnel of the railway line Rome-Florence in 1863.
The area at the confluence of Valdarno, Valdichiana and Casentino, infact, is a natural step for those who want to cross the Apennines. Then there is news of permanent settlements of pre-Etruscan in an area not far from the current urban area, the hill of St. Cornelius, where they found traces of a wall difficult to date because stamped by the mighty Roman walls. The Etruscan settlement was built instead on the hilltop of San Donato, occupied by the city. We know that the Etruscan Arezzo, called “Arıtım” (Latin Arretium), already existed in the ninth century BC
Arezzo was then one of the major Etruscan cities, and most likely home to one of 12 lucumonie. To this period belong the works of art of exceptional value, such as the Chimera, preserved in Florence, whose image characterizes the city so as to become almost a second symbol and also noteworthy is the large necropolis of Poggio del Sole, formed in VI century BC and used to Roman times.
The rising power of Rome, the city, along with Etruscan sisters, tried to contain the expansionist tendencies, but the army put together by Arezzo, Perugia and Volterra was defeated in Roselle, near Grosseto, in 295 BC; and so in the third century BC Arezzo was conquered by the Romans who latinized his name Etruscan Arretium.