Chi Rho

Lore & Background

The Chi Rho (☧) is an early Christian symbol formed by superimposing the first two capital letters of the Greek word for Christ—chi (Χ) and rho (Ρ)—so that the vertical stroke of the rho crosses the center of the chi. It is one of the earliest forms of the Christogram. The Roman emperor Constantine the Great used the Chi Rho as part of a military standard known as the Labarum. According to the historian Lactantius, Constantine dreamt he was ordered to place a “heavenly divine symbol” on his soldiers’ shields; the next day his army won the Battle of the Milvian Bridge. Eusebius of Caesarea later recorded that Constantine saw a cross of light over the sun with the Greek words “In this, conquer,” and that Christ appeared in a dream instructing him to replicate the sign. The Chi Rho appears on Constantine’s coins and medallions, and by the year 350 it was used on Christian sarcophagi and frescoes. The usurper Magnentius first minted coins with the Chi Rho flanked by Alpha and Omega. In pre-Christian times, the symbol marked valuable passages in margins, abbreviating the Greek word for “good.” Coins of Ptolemy III Euergetes also bore a Chi Rho. The device frequently served as an abbreviation in Latin texts, with endings such as “XPo” for “Christo” (to Christ). A 4th-century mosaic from Hinton St. Mary, Dorset, depicts a male bust before the Chi Rho flanked by pomegranates.

Reader's Guide

The Chi Rho monogram, formed by overlapping the Greek letters chi and rho, was adopted by the Roman emperor Constantine the Great as part of a military standard called the Labarum. According to the historian Lactantius, Constantine dreamt he was ordered to place a heavenly divine symbol on his soldiers’ shields before the Battle of the Milvian Bridge; the description of that symbol closely resembles a Tau-Rho or staurogram. Eusebius of Caesarea later provided a different account, writing that Constantine saw a cross of light over the sun with the Greek words “In this, conquer,” and that Christ appeared in a dream instructing him to replicate the sign. Eusebius claimed Constantine himself confirmed this story with oaths. The Chi Rho was subsequently emblazoned on Late Roman helmets and appeared on Constantine’s coins and medallions. By 350, it was used on Christian sarcophagi and frescoes. The usurper Magnentius was the first to place the Chi Rho flanked by Alpha and Omega on coin reverses in 353. A 4th-century mosaic from Hinton St. Mary in Roman Britannia depicts a male bust in front of the Chi Rho. In pre-Christian times, the symbol marked valuable passages in margins, abbreviating the Greek word for “good,” and appeared on coins of Ptolemy III Euergetes. The Chi Rho is one of the earliest Christograms, and when flanked by Alpha and Omega, it spells the Greek word for “I rule.” It also served as an abbreviation in Latin texts, with endings added to form words like “Christo” or “Christicola.”

Did You Know?

• The Chi Rho is formed by superimposing the first two capital letters chi and rho (ΧΡ) of the Greek word "ΧΡΙΣΤΟΣ", meaning Christ.
• It was used by the Roman emperor Constantine I as a vexillum named the Labarum.
• The symbol was widespread in ancient Christianity.
• The monogram is produced by superimposing chi and rho in such a way to produce the monogram.