On Lammas Day 1086 [August 1st], William the Conqueror, king of England, summoned 170 of his tenants-in-chief and other landowning men of any account to Old Sarum, where they all swore allegiance in person to him and to be faithful against all other men.
Statuimus, ut omnes liberi homines faedere et sacramento affirment, quad intra et extra universum regnum Angliae Wilhelmo regi domino suo fideles esse volunt; tenas et honores illius omni fidelitate ubique servare cum eo, et contra inimicos et alienigenas defendere. @@@
Known as the Salisbury Gemot (oath) in the Anglo-Saxon Chronicle, this was the act which first established feudalism in England.