Saint Michael's Altar and Reredos by Louis Comfort Tiffany
From a pamphlet available in the narthex (entrance) of the church, “A Brief Tour and Description of St. Michael’s Church Interior and Windows,” by church Archivist Jean Ballard Terepka:
“Reredos is from two Latin-French words meaning rear and back. The reredos behind the High Altar is in the form of a mosaic set against and into the wall. It contains four medallions representing a winged man, a winged lion, a winged bull and an eagle; each holds a book. These are the four cherubim described in Ezekiel I & I ad the four beasts or creatures of Revelation IV and V. In Christian art, they also represent the four evangelists, Matthew, Mark, Luke and John, who proclaim to the world Jesus Christ as the revelation of God in the world.
The High Altar is of white marble, framed in a rich yellow marble, set against a dark background in order to make it the most conspicuous object in the church. In the center is a square cross constructed of circles running into one another. In the fields at the angles of the cross are inscribed in Greek the first and last letter of Jesus and Christ , “IΣ” and “X Σ” (IS and XS) and the Greek acronym, “NI-KA” (i.e., Jesus Crhist conquers by the Cross). In the long panels at the corners of the altar, and on both ends, is depicted the victory of the cross by the cross standing on the world. Between the cross in the center and the crosses in the corners, is a triangle of smaller circles and combining with the Triangles of the Trinity.“