Chi Rho - Wikipedia

The Chi Rho (/ ˈ k aɪ ˈ r oʊ /; also known as chrismon or sigla) is one of the earliest forms of christogram, formed by superimposing the first two (capital) letters—chi and rho (ΧΡ)—of the Greek word ΧΡΙΣΤΟΣ in such a way that the vertical stroke of the rho intersects the center of the chi.. The Chi-Rho symbol was used by the Roman emperor Constantine I (r. 306–337) as part ...…