The Chi Rho page (folio 34R) of the <a href="//commons.wikimedia.org/wiki/Book_of_Kells" title="Book of Kells">Book of Kells</a>. The page precedes the nativity story as related by St Matthew. The letters Chi, Rho and I are an abbreviation of "Christ".
unknown Irish or Scottish monks
circa 800AD
Website of the Book of Kells on CD-ROM