Chi Rho
Videos
The Chi Rho is one of the earliest forms of the Christogram, formed by superimposing the first two letters—chi and rho —of the Greek ΧΡΙΣΤΟΣ in such a way that the vertical stroke of the rho intersect
Missorium depicting Emperor Constantine the Great's son Constantius II accompanied by a guardsman with the Chi Rho depicted on his shield (at left, behind the horse)
Coin minted during reign of Ptolemy III Euergetes in Egypt (from 246 BC to 222 BC). Chi Rho visible between bird's legs.
This coin of Crispus, son of Constantine, with a chi rho on the shield (struck c. 326) shows that the symbol mentioned by Lactantius and Eusebius was a chi rho.
The so-called "Chrismon of Saint Ambrose" (Chrismon Sancti Ambrosii), on display on the eastern wall of Milan Cathedral, a Chi-Rho combined with Alpha and Omega in a circle. According to Landulf of Milan (12th century), it was used by Saint Ambrose to introduce the catechumens to the mysteries of the Christian faith (whence it was called "oracle" or chresmos of St. Ambrose, written by Landulf as crismon, whence the later Neo-Latin term for the Chi-Rho symbol).
Alpha and Omega
Videos
Alpha and Omega are the first and last letters of the Greek alphabet, and a title of Christ or God in the Book of Revelation. This pair of letters is used as a Christian symbol, and is often combined
Chi Rho
…Early symbols similar to the Chi Rho were the Staurogram (⳨) and the IX monogram (). When flanked by the first and last letters of the Greek alphabet, Alpha and Omega, the symbol spells Ᾰ̓́ΡΧⲰ (rom: archo), "I rule". Although formed of Greek characters, the device (or its separate parts) is frequently found serving…
The Chi-rho symbol with Alpha and Omega, Catacombs of Domitilla, Rome
The Greek letters alpha and omega surround the halo of Jesus in the catacombs of Rome from the 4th century.
"ΑΩ" in stained glass