Library Eusebius of Caesarea Life of Constantine
Book 3
Chapter 52: Constantine's Letter to Eusebius concerning Mambre
Victor Constantinus, Maximus Augustus, to Macarius, and the rest of the bishops in Palestine.
One benefit, and that of no ordinary importance, has been conferred on us by my truly pious mother-in-law, in that she has made known to us by letter that abandoned folly of impious men which has hitherto escaped detection by you: so that the criminal conduct thus overlooked may now through our means obtain fitting correction and remedy, necessary though tardy. For surely it is a grave impiety indeed, that holy places should be defiled by the stain of unhallowed impurities. What then is this, dearest brethren, which, though it has eluded your sagacity, she of whom I speak was impelled by a pious sense of duty to disclose?
English translation by Ernest Cushing Richardson, in Nicene and Post-Nicene Fathers, Series II, Vol. I (eds. Philip Schaff and Henry Wace; Buffalo: Christian Literature Publishing Co., 1890). Public domain. Digital text via New Advent Church Fathers.