In the old catacombs of St. Sebastiano, St. Calisto, St. Lorenzo, and Sta. Agnese at Rome, extending altogether to about 750 miles, and in those of St. Gennaro de Poveri, Sta. Maria della Sanitá, and Sta. Maria della Vita at Naples, we find some attempts at symbolism; the cross, the monogram of Christ’s name ΧΡ {CHR}; or an ΑΩ {AÔ}, symbolical of the beginning and the end of all things; a palm branch, doves, the piscis vesica, and here and there a lamb. But these signs belong to the fourth and fifth centuries A.D. The inscriptions do not go farther back than the second century. The homely simplicity of the early Christians is distinctly to be traced in the absence of all symbolic decoration during the first two centuries. Gradually the Christians passed through the phase of geometrical ornamentation. Triangles and circles, crosses and squares, squares divided into four squares, or the square taken three times, giving twelve points, which number contains the sacred numbers; three (the Trinity), five (the five sacred wounds of Christ), seven (the seven cardinal virtues, or the seven days of Creation), and twelve (the twelve apostles), made their appearance. Seven was a holy and mystic number with all the ancient nations. There were seven planets, and seven colours in olden times; Apollo’s lyre had seven strings; Pan used seven pipes for his flute. There are seven days of the week; seven or three times seven are the critical days in medicine; there were seven branches to the candlestick of the Jews in the Temple of Jerusalem. Seven years Jacob had to serve for Leah; and seven others for Rachel; seven were the ears and kine of which Pharaoh dreamt; seven were the gods in Scandinavian mythology; seven were the sufferings of the Virgin Mary; seven the cardinal virtues; seven the deadly sins; seven are the sacraments of the Romish Church. We cannot fail to see in the minutest details of history and art, philosophy and religious systems, an eternally progressing ‘one-ness’ pervading humanity as a great whole. Scarcely had the Christians adopted these signs, when they passed on to the next phase, adorning churches and tombs, altars and sacred vessels, with emblems taken from the vegetable and animal kingdoms, to serve as the holy visible outward signs of some sacred inward grace or virtue. What was immortal was to be expressed in mortal forms, and the finite was to embody the infinite. Again, the meaning hallowed the form; again, by degrees, the _form_ became all, and the spirit was altogether lost through the mere outward sign. Art suffered for centuries under the gloomy pressure of symbolism, and in striving to disentangle itself, produced marvels, but it was only freed and attained higher forms of beauty again, when humanity had gone back to those laws, which when followed out had produced forms perfect in themselves.