Near the steps of the tribune are two marble slabs, on which Pius IX. has immortalised the names of the cardinals and bishops who, on December 8, 1854, accepted, on this spot, his dogma of the Immaculate Conception.

Turning towards the left transept;—on the left is a mosaic of St. Peter healing the lame man, from Mancini. On the right is the tomb of Alexander VIII., Pietro Ottobuoni (1689—91), by Giuseppe Verlosi and Angelo Rossi, gorgeous in its richness of bronze, marbles, and alabasters. Beyond this is the altar of Leo the Great, over which is a huge bas-relief, by Algardi, representing S. Leo calling down the assistance of SS. Peter and Paul against the invasion of Attila.

"The king of the Huns, terrified by the apparition of the two apostles in the air, turns his back and flies. We have here a picture in marble, with all the faults of taste and style which prevailed at that time, but the workmanship is excellent; it is, perhaps, the largest bas-relief in existence, excepting the rock sculpture of the Indians and Egyptians—at least fifteen feet in height."—Jameson's Sacred Art, p. 685.

Next to this is the Cappella della Colonna, possessing a much revered Madonna from a pillar of the old basilica, and beneath it an ancient Christian sarcophagus containing the remains of Leo II. (ob. 683), Leo III. (ob. 816), and Leo IV. (ob. 855). In the pavement near these two altars is the slab tomb of Leo XII. (ob. 1828), with an epitaph illustrating Invocation of Saints, but touching in its humility.

"Commending myself, a suppliant, to my great celestial patron Leo, I, Leo XII., his humble client, unworthy of so great a name, have chosen a place of sepulture, near his holy ashes."

Over the door known as the Porta Sta. Marta (from the church in the square behind St. Peter's, to which it leads), is the tomb of Alexander VII., Fabio Chigi (1655—67), the last work of Bernini, who had built for this pope the Scala-Regia and the Colonnade of St. Peter's. This is, perhaps, the worst of all the papal monuments—a hideous figure of Death is pushing aside an alabaster curtain and exhibiting his hour-glass to the kneeling pope.

Opposite to this tomb is an oil painting on slate, by Francesco Vanni, of the Fall of Simon Magus. The south transept has a series of mosaic pictures; The Incredulity of St. Thomas from Camuccini, the Crucifixion of St. Peter and a St. Francis from Guido, and, on the pier of the Cupola, Ananias and Sapphira from the Roncalli at Sta. Maria degli Angeli, and the Transfiguration from Raphael.[337]

Opposite the mosaic of Ananias and Sapphira is the last tomb erected in St. Peter's, that of Pius VIII., Francesco Castiglione (1829—31), by Tenerani. It represents the pope kneeling, and above him the Saviour in benediction, with SS. Peter and Paul. It is of no great merit.

The Cappella Clementina has the Miracle of St. Gregory the Great from the Andrea Sacchi at the Vatican. Close to this is the fine tomb of Pius VII., Gregorio Chiaramonte (1800—23), who crowned Napoleon,—who suffered exile for seven years for refusing to abdicate the temporal power,—and who returned in triumph to die at the Quirinal, after having re-established the Order of the Jesuits. His monument is the work of Thorwaldsen, graceful and simple, though perhaps too small to be in proportion to the neighbouring tombs. The figure of the pope, a gentle old man (he died at the age of eighty-one, having reigned twenty-three years), is seated in a chair; figures of Courage and Faith adorn the pedestal. The tomb was erected by Cardinal Gonsalvi, the faithful friend and minister of this pope (who died very poor, having spent all his wealth in charity), at an expense of 27,000 scudi.

Turning into the left aisle,—on the right is the tomb of Leo XI., Alessandro de Medici (1605), to which one is inclined to grudge so much space, considering that the pope it commemorates only reigned twenty-six days. The tomb, in allusion to this short life, is sculptured with flowers, and bears the motto, Sic Florui. It is the work of Algardi. The figures of Wisdom and Abundance, which adorn the pedestal, are fine specimens of this allegorical type.