Chi Rho are the first two letters in the Greek spelling of the word Christ (Greek : "Χριστός") and so have come to be used for a number of Christian-related usages. The Chi Rho is one of the earliest cruciform symbols used by Christians. It is formed by superimposing the first two letters of the word "Christ" in Greek, chi = ch and rho = r. Although not technically a cross, the Chi Rho invokes the crucifixion of Jesus as well as symbolizing his status as the Christ. The term Alpha and Omega comes from the phrase "I am the alpha and the omega" (Ancient Greek: τὸ Α καὶ τὸ Ω), an appellation of God in the Book of Revelation (verses 1:8, 21:6, and 22:13). Its meaning is found in the fact that Alpha (Α) and Omega (Ω) are respectively the first and last letters of the Classical (Ionic) Greek alphabet. Cimetière de Picpus, Paris, France