The University of Oxford, informally Oxford University or simply Oxford, is a collegiate research university located in Oxford, England. It has no known date of foundation, but there is evidence of teaching as far back as 1096, making it the oldest university in the English-speaking world and the world's second-oldest university in continuous operation. It grew rapidly from 1167 when Henry II banned English students from attending the University of Paris. After disputes between students and Oxford townsfolk in 1209, some academics fled north-east to Cambridge where they established what became the University of Cambridge. The two "ancient universities" are frequently jointly referred to as "Oxbridge".