The origin of the Tiber

The origins of the Tiber river: the big Tiber lake. In the final period of the Pliocene and during the whole period of the Pleitocene the tectonic hollow , nowadays crossed by the river Tiber, was covered by a lake of impressive dimension. It streched out N-W and S-E as far as Perugia and then it divided into two arms: one arrived near Spoleto and the other near Terni.The deforming forces continuously provoke the origin and the reactivation of the big faults and a continuous sinking of the hollow.

The river Tiber

The river Tiber is now recovering its charm remaining a big natural attraction. Thanks to the efforts of the city administration for the purification of the urban unloading, a great variety of fish such as bleaks (Alburnus Alburnus), rudds (Scardinius erythrophthalamus), Crucian carps (Carassius carassius), numerous eels (Anguilla anguilla), carps and mullets have returned to populate the waters of the Tiber river. However, sturgeons(Acipenser sturio), which went up the course of the river once, never came back. 

Its water route

Several million years ago what is now the Tiber Valley was an enormous lake (Lake Tiberino) that extended from Sansepolcro to Terni and Spoleto, dividing into two branches at about Perugia.

Fossil remains show what kind of animals populated the banks of the lake (rhinoceros, hippopotami, elephants, hyenas, megaceros). Following a movement of the tectonic plates, the lake dried up and left the valley with the Tiber running through it. The Tiber Valley became the border between the Umbrian and Etruscan populations, but it was above all the Romans who were responsible for developing an infrastructure of links between the towns, camps and army posts.      

Ponte Fabricio

The island of  Esculapio was already connected to the left bank by a wooden bridge around 192 b.c.

A similar structure was supposed to be in 62 b.c. Fabricio, responsible to the roads, transformed it in a solid stone bridge.

DESCRIPTION

The bridge, 62 m long and 5,5 m wide, has two large arches and a central pier with a hole to reduce the  load   of the flood water. The inner nucleus consists of tufo and peperino,  the externat structure is of travertino blocks, while the covering is a brickwork.

LEGEND AND CURIOSITIES

As many already know, Sisto V reigned for five years and made five roads, five fountains, five spires, five bridges and left five millions inside the castle (castle S. Angelo).

THE TIBER ISLAND

History

 The Tiberina Island, formerly simply called “Insula” or “Insula inter duos pontes”, afterwards was also called “Lycaonia” in the Middle Ages and “of St. Bartholomew” in ‘600-‘700.

Generated, according to legend, by the mud amassed on the Tarquinio il Superbo crops, thrown to the river by Romans when they expelled the king from the town, really the island is tufaceus, like the hills near Rome.

Description

The island still keeps the characteristic shape of the ship of Esculapio. Under the hanging stairs flight of the Fluvial Police station, the rests of the monumental ship shape arrangements of the tip of the island, contemporary to the Fabricio bridge, can be seen. On the travertine blocks that cover the inner nucleus in peperino, you can see the carved bust of Esculapio, the snake rolled up around the stick, God Symbol and one taurine protome.

Legends and curiosities

The ancient traveller, arriving to the Insula from the Pons Fabricius, would have noticed to his left the sanctuary of the healer God Esculapio = Asclepius.

The embankments

The destiny of the Tiberina island was in doubt at the end of 1800, after Rome became the capital of Italy. In fact, it was stated to give the Tiber a definitive arrangement in accordance to the new role of the town.

Ponte rotto

At the beginning of Rome's history, there was just a single line of communication between the city and Etruria: the road that, through the Sublicio bridge, crossed Trastevere [meaning: beyond the Tiber] plain near St. Cosimato and steep rise to the Gianicolo. Things improved in the VI century of Rome(II b.C.), when a new road, the present Lungaretta, and a new bridge were built.

The old "Pons Aemilius" was the first in stone on the Tiber (the Sublicio Bridge was wooden). It was erected in two steps: in 181-179 b.C. the censors Marco Emilio Lepido and Marco Fulvio Nobiliore raised the pillars that supported a wooden footbridge that, on 142 b.C., was replaced by four masonry arches by Publio Scipione Emiliano and Lucio Mummida.

Ponte Cestio

Its construction, dating back to 46 b.C., is ascribed to Lucio Cestio, one of the magistrates to which Caesar entrusted the administration of the town during his campaign in Spain.

The old bridge was almost 50 m long and had one central lower curve arch and two smaller ones about 6 m long.

It was restructured by Aurelio Avianio Simmaco, Praefectus Urbi, during emperors Valentiniano, Valente and Graziano's rule; the bridge was dedicated to the latter during the spring of 370 AD and therefore named "pons Gratianus".

In 1191-93 the bridge, by then "fere dirutum" (nearly destroyed), as indicated on the inscription still located on the bridge parapet, was restored again by Benedict Carushomo (Carissimi), sole senator of the town.

On late 1400 it was named "of St. Bartolomeo" (from the same name church on the island) and in the 1700-1800 "iron bridge".

According to the Canevari project, that stated a width of 70 m for this branch of the Tiber near the island, the bridge was disassembled in 1888 and rebuilt in three equal arches,

Employing the original materials as much as possible, it was completed in 1892. During such remake it was discovered that in the IV century Simmaco used for the restoration some travertine blocks taken from the inferior order (Doric) of the Marcello theatre and some historical tablet of the Trajan age.

After the 1900 flood, the two large lateral arches were "bridled" (1901) in order to restore the previous water flow.

The present restoration has been carried out within the works foreseen in Rome for the 2000 Jubilee.