The Book of Kells and the Book of Durrow are both illuminated Gospel books in the medieval Celtic tradition, and they both contain a page presenting the famous Chi-Rho symbol (the first two Greek letters of Christ's name). They show the Chi-Rho in quite different styles, however. Let's take a look at each of these beautiful manuscripts.
The Book of Kells uses the traditional Celtic interlace, knots, spirals, and patterns. Organic elements like leaves intertwine with geometric patterns. Stylized angels peek out from various places in the image, and a face looks from just below the center. The colors are vibrant and varied. The Chi-Rho occupies the entire page, making it a "carpet page." The effect is stunning indeed, and one could look at it for hours, tracing the patterns, trying to untie the knots, and noticing new elements.
The Book of Durrow's "Chi-Rho" page is much simpler. In this case, the Chi-Rho occupies only part of a page. It is inserted between lines of the Gospel of Matthew text and actually forms the the beginning of a word. The primary parts of the letters are in gold, and they branch out in Celtic spirals and show influence of the circular, trumpet-like La Tene style. This Chi-Rho is not nearly as colorful as the one in the Book of Kells, but it is appealing it is own right, for it displays an elegance in its curves and lines.