Oath to a Lord -- from the 9th Century

Thus shall one take the oath of fidelity: By the Lord before whom this sanctuary is holy, I will to N. be true and faithful, and love all which he loves and shun all which he shuns, according to the laws of God and the order of the world. Nor will I ever with will or action, through word or deed, do anything which is unpleasing to him, on condition that he will hold to me as I shall deserve it, and that he will perform everything as it was in our agreement when I submitted myself to him and chose his will.

E.P.Cheyney, trans., University of Pennsylvania Translations and Reprints, Vol IV, No. 3. Philadelphia: University of Pennsylvania Press, 1898.