This Christian symbol, called a Christogram, was used by the early church and was often found on official seals and coins after the Roman Empire became Christian. It is similar to the CHI RHO, formed of the Greek letters X and P and which are a monogram for the name of Christ. The Christogram was also adorned much early Christian art and illuminated manuscripts. Many Christograms were also embellished by the Greek letters Alpha and Omega attached to the arms of the cross. These letters were the first and last of the Greek alphabet and refers to Jesus words "I am the Alpha and the Omega"meaning that Jesus was the beginning and the end, encompassing all things.