In hoc signo vinces
"In hoc signo vinces" is a Latin phrase conventionally translated into English as "In this sign thou shalt conquer"; alternate transl. "By and/or in this sign, be victorious".
The Latin phrase renders loosely the Greek phrase "ἐν τούτῳ νίκα (en toútōi níka)", lit. 'in this, be victorious'.