The Arms of the University of Oxford show an open book with the inscription 'Dominus illuminatio mea' (The Lord is my light), surrounded by three golden crowns.
A blazon of this would be:
Azure, upon a book open proper, leathered gules, garnished or, having on the dexter side seven seals of the last, the words DOMINVS ILLVMINATIO MEA; all between three open crowns, two and one, or.[1]
The arms have been in existence since around 1400, varying in appearance over the centuries. The number of seals and the text, for example, have both varied. The modern version of the arms in which they are not borne on a shield, but rather surrounded by a garter bearing the text 'UNIVERSITY OF OXFORD' was designed in 1993 and is a registered trademark.