Later the papal government undertook many great public works.  The Venetians had, as we shall see, re-fortified Ravenna; these fortifications the papal government enlarged, and in the middle of the seventeenth century undertook the digging and construction of the Canale Pamfilio, so named in honour of Innocent X., and in the following century of the Canale Corsini.  These works were necessary, it is said, not only for the maritime commerce of the city, which one may think was scarcely large enough to have excused them, but for the preservation of Ravenna from inundation consequent upon the silting up of the rivers.

But the earliest work done in Ravenna after the close of the Middle Age was that undertaken by the Venetians.  It was in 1457 that they began to build the really tremendous fortification or Rocca, the ruins of which we may still see.  They were engaged during some ten years upon this great fortress, the master of the works being Giovanni Francesco da Massa.  They employed as material the ruins of the church of S. Andrea dei Goti, built by Theodoric, which they had been compelled to destroy to make room for the fortress, as well as the materials of a palace of the Polentani.  The Rocca with its great citadel played a considerable part in the battle of 1512, and the subsequent sack of the city.  But when Ravenna came again into the government of the Holy See, though the fortifications of the city as a whole were enlarged, the Rocca itself soon fell into a decay and was indeed in great part destroyed in the middle of the seventeenth century, the monastery and the church of Classe being repaired and enlarged with its ruins and the Ponte Nuovo over the Fiumi Uniti, according to Dr. Ricci, being also constructed from its remains, as were other buildings in Ravenna.  Then like the Rocca Malatestiana at Rimini it came to be used as a mere prison, and when it failed to prove useful for that purpose it was allowed to become the picturesque ruin we see.

Upon the Torre del Ponte of old were set two great reliefs; on high the Madonna and Child and beneath the Lion of S. Mark.  The Madonna and Child, a mediocre work, remains, but when Venice was turned out of Ravenna the Lion was taken down and behind it were carved the papal arms.  Both Madonna and Lion would seem to have been the work of Marino di Marco Ceprini.

Another work undertaken and achieved by the Venetians was the enlargement and the adornment of the Piazza Maggiore.  There in 1483, when their work was finished, they raised two columns which still stand before the Palazzo del Comune.  They stand upon circular bases in three tiers, sculptured in relief by Pietro Lombardi with the signs of the Zodiac and other symbols and ornaments.  The capitals of both the columns are beautiful.  Upon the northern column of old stood a statue of S. Apollinaris, the true patron of the city, while upon the southern column stood the Lion of S. Mark.  But when in 1509 Ravenna