03:1503:15, 9 March 2022diffhist0
Pacta sunt servanda
AD is put before individual *year numbers*, this doesn't extend to centuries. This is easily seen by substituting AD with the English: "in the year of our lord 1215" works, but "in the year of our lord 13th century" doesnt. The AD here isn't even needed at all, if anyone wishes to remove it altogether