Edward I (1239 –1307) is alleged to have gone to Cambridge and declared it to be ‘an open university – open to all’, thus making him one of the earliest users of the term Open University. However, Henry Goulburn, the MP for Cambridge who spoke in the Commons on 28 July 1834, (this from a report of the Commons Debate in The Times 29.7.1834) argued this was unlikely as on Edward’s death the only known college in Cambridge was Peterhouse. Still, an alleged use of the term in about 1300 makes this the earliest reference. Unless, of course you know of earlier uses of the term.
Image credit: This image is in the public domain.