Greek, not Latin. It's called the Chi Rho for the first two letters of Christ in Greek - ΧΡΙΣΤΟΣ.
https://en.m.wikipedia.org/wiki/Chi_Rho
Greek, not Latin. It's called the Chi Rho for the first two letters of Christ in Greek - ΧΡΙΣΤΟΣ.
https://en.m.wikipedia.org/wiki/Chi_Rho