Sometimes I despair that so much knowledge that was once standard is now hardly known and that therefore its rediscovery becomes the source for proud scholarly papers and articles.
Have a look at this picture from a manuscript of Isidore of Seville's Etymologicae (full manuscript here)
C(h)risimon. Haec sola ex voluntate uniuscuiusque ad aliquid notandum ponitur.
Phi et Ro, id est FRONTIS. Haec, ubi aliquid obscuritatis est, ob sollicitudinem ponitur. (Latin text of Isidore found here)
How many of us will have tried to find some Christological link when seeing the Chi / Rho sign in the margin of a manuscript?