"The Tarquins had sacrilegiously converted the best part of the Campus
Martius to their own use. When they were expelled, it happened to be
harvest time, and the sheaves then lay upon the ground; but as it was
consecrated, the people could not make use of it. A great number of
hands, therefore, took it up in baskets and threw it into the river.
The trees were also cut down and thrown in after it, and the ground
left entirely without fruit or produce for the service of the god. A
great quantity of different sorts of things being thus thrown in
together, they were not carried far by the current, but only to the
shallows, where the first heaps had stopped. Finding no further
passage, everything settled there, and the whole was bound still
firmer by the river; for that washed down to it a deal of mud, which
not only added to the mass, but served as a cement to it, and the
current, far from dissolving it, by its gentle pressure gave it the
greater firmness. The bulk and solidity of this mass received
continual additions, most of what was brought down by the Tiber
settling there. It was now an island sacred to religious uses. Several
temples and porticoes have been built upon it; and it is called in
Latin _inter duos pontes_--the island between the two bridges"
(Plutarch, in "Publicola").
The island in the Tiber is an alluvial formation, and thus far the
legend is correct in ascribing its origin to the accumulation of
rubbish and drifted sand. In remembrance of the vessel which bore the
statue of Æsculapius from Epidaurus to Rome, the entire island was
faced with stone, and made to assume the form of a ship, in which was
placed the temple of the god.
Some of the immense blocks of travertine composing the facing, and
representing the hull of the ship, may still be seen in the monastery
garden of the Church of S. Bartolomeo in Isola. _Ladies are not
admitted to the monastery._
"In the island of the Tiber, just prior to the death of Otho, the
statue of Julius Cæsar turned from west to east, a circumstance said
likewise to have happened when Vespasian took on him the empire"
(Plutarch).
In the Piazza is a monument to SS. John, Francis, Bartholomew, and
Paulinus. The interior of the church is embellished with fourteen
ancient columns, and in the choir are the remains of an early mosaic.