One of the enduring images of Christian art is Christ the Good Shepherd rescuing his sheep. This image is from the Catacombs of Priscilla in a former Roman quarry used for burial from the end of the 2nd to the beginning of the 4th centuries:

In this same location is the oldest known representation of Mary the Virgin Mother of Christ, nursing the baby Jesus alongside the evil prophet Balaam:

I shall see him, but not now: I shall behold him, but not nigh: there shall come a Star out of Jacob, and a Sceptre shall rise out of Israel, and shall smite the corners of Moab, and destroy all the children of Sheth.
~ King James Bible, Numbers 24:17
The Catacombs of Rome are preserved by the International Catacomb Society and are open for visitation.