The first archaeological evidence consisting trace the first settlement in the area in the Iron Age, with rich funerary objects from the VIII century B.C. the Etruscan city of Clevsi, became the Latina Clusium (Klysion Κλύσιον, in ancient Greek), had a fundamental importance, since located on the artery that connected Rome to the northern Etruria, following the Tiber and its main tributary the Clanis, being the valley bottom of the homonymous valley extremely fertile. The summit of his power lies at the end of the VI century B.C. when, under the guidance of King Porsenna, besieges and controls for a short period, Rome. In 89 B.C., with the extension to its inhabitants of Roman citizenship, Chiusi enters fully into the political orbit of Rome. Its prosperity continues even in the Imperial Age, during which Chiusi-Clusium remains an important transit point on the via Consolare Cassia and river Clanis, then navigable to the Tiber. From the III century A.D. the city became an important center for the spread of Christianity, as witnessed by the catacombs of Santa Mustiola and Santa Caterina and the Cathedral of S. Secondiano. In the following centuries closed is also the seat of a Lombard Duchy, after which begins a long period of decadence. The time most critical of its history coincides with the swampiness of Chiana Valley and only in the nineteenth century the complete reclamation of the valley the returns importance.
Chiusi is famous for the splendid Etruscan remains, innumerable excavations have brought to light findings are unique in the world, such precious testimonies are exposed at the National Etruscan Museum of Archeology, which certainly deserves a visit. The museum is articulated in three sections in which it traces the history of Chiusi through the exposure of numerous archaeological masterpieces, vases, terracottas and funerary sculptures. Between the Etruscan tombs, most remarkable are the tomb of the pilgrim, the tomb of the Monkey, the Pania and the tomb of the Lion. Not many years it has been opened to the public an interesting route, the so-called maze of King Porsenna, an intricate system of underground passages of the Etruscan Age, and that passing through the subsoil of Chiusi, leads to a monumental cistern dating back to the I century AD. Of the first Christian age are the catacombs of Santa Mustiola and Santa Caterina.
In front of the Archaeological Museum there is Piazza del Duomo, monumental heart of Chiusi. The Cathedral was built in the XII century and and next to it there is the Museum of the Cathedral which preserves important finds, between which the precious manuscripts Benedictines. To the left of the Cathedral there is the tower of San Secondiano, built in the XII century and transformed into a bell tower in 1585. From Piazza del Duomo we can follow the ancient Decuman (via Porsenna), along this way are some interesting buildings among which: the palace Bonci Casuccini, former Fanelli palace, today Baldetti, of the XV century and the Palazzo Della Ciaia of the XVI century. Continuing in via Arunte it then comes to the Prato from which you can enjoy a beautiful panorama, from here you can catch a glimpse of the Fortress of the XII century, today private property. Taking Via Paolozzi you arrive at the church of San Francesco with the adjacent convent with a beautiful cloister, you then enters piazza XX Settembre where are the Palazzo Comunale, the Clock Tower and the Logge, in addition to what we find the Church of Santa Maria of death. The city walls, largely demolished to reuse the stones or during the second world war, they remain only some sections between which a single gate (Porta Lavinia) of three that there were originally.