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).
Eusebius of Caesarea, also known as Eusebius Pamphilius, was a historian of Christianity, exegete, and Christian polemicist from the Roman province of Syria Palaestina. In about AD 314 he became the b
6th century Syriac portrait of St. Eusebius of Caesarea from the Rabbula Gospels
Armenian translation of Chronicon. 13th century manuscript.
Eusebius's canon tables were often included in Early Medieval Gospel books.
Eusebius depicted in the page preceding his Eusebian Canons in the ancient Garima Gospels