JTP is right of course, Constantine I's Labarum is also known as a Chrismon, Chi-Rho (from the two Greek letters that make it up) or monogram of the name Jesus Christ.
Somewhat pedantically the Chi-Rho references the Greek Iesous, the Greek for the original Hebrew "Yeshua" and Christos, the Greek "anointed one" rather than our recognizable Jesus the Christ, which is actually from the Latin...
Well yes, if we want to be really pedantic the chi-rho would translate to the hebrew taw-resh which in phoenician script gives the X and and a reversed form of P. The Phoencian letters gave rise to the greek tau & rho and latin R & T and cyrilic Te and P.
You've no need to impress me, Octavius...I've appreciated your thorough expositions for some time. I simply felt it necessary to point out that the English Jesus Christ, isn't the basis for the originally asked question, which, I believe you stated in your other wise succint answer. No criticism intended on my part...