After the time of Constantine, when the Christians were no longer forced to hide their art in the catacombs, they began to have a sculpture of their own. The first Christians in Rome were brought into contact with the worship of Isis and Pan, Venus and Apollo, and were filled with horror at the sight of the statues of these divinities. They believed that any representation of the human form was forbidden by the commandment which says, "Thou shalt not make to thyself any graven image, nor the likeness of anything that is in the heaven above, or in the earth beneath, or in the water under the earth." Thus it happened that when the early Christians desired to represent the Saviour they employed painting, such as is found in the catacombs, rather than sculpture, and separate statues are the rarest remains of early Christian art. The oldest Christian statue which is known in marble is that of St. Hippolytus, which is in the Museum of the Lateran Palace, where there are also two small statues of Christ as the Good Shepherd, which were found in the catacombs. [Illustration: FIG. 71.--STATUE OF ST. PETER.] The most important statue of this period is that of St. Peter, which is held in great reverence by Roman Catholics, who kiss its toe as they enter the church of St. Peter's at Rome, and press their foreheads against the extended foot. The statue is of bronze, and some antiquarians believe that it is the Jupiter of the Capitol changed so as to answer for a statue of St. Peter; others say that it was cast from the metal of the statue of Jupiter; and the usual belief is that it was made by the order of Pope Leo I. about the middle of the fifth century as a thank-offering for the deliverance of Rome from the barbarian Attila by the miraculous protection of St. Peter and St. Paul. This statue is too rude to belong to classic art, though it is of remarkable excellence for a work of the fifth century (Fig. 71). The principal use of sculpture by the early Christians was for the decoration of the sarcophagi, or burial-cases. These were cut in bas-reliefs after the manner of the ancients, the subjects being taken from the life of Christ; the ornaments were the Christian emblems, such as the lamb, cross, vine, palm, dove, and the monogram of Christ. As time passed the designs were more and more elaborate; stories from the Old Testament were frequently illustrated, and numerous figures were crowded together, with many symbols ingeniously inserted to make the meaning of the whole more clear.