thanks for the article, I did not know that.
the chi-rho was also used on Greek coins for a control mark, maybe the initials of someone.
Ptolemaic Kingdom of Egypt, Ptolemy III Euergetes. Æ Diobol (29mm 21.0gm) Alexandria, circa 245-222 B.C.; Diademed head of Zeus-Ammon right / BAΣIΛEΩΣ ΠTOΛEMAIOY, eagle left on thunderbolt; in front cornucopiae; between legs chi-rho monogram. SNG Copenhagen 176-177.