The University of Oxford (informally Oxford University, or simply Oxford) is a university in Oxford, England. It is the second oldest surviving university in the world and the oldest in the English-speaking world. Although the exact date of its foundation remains unclear, there is evidence of teaching there as far back as the 11th century. The University grew rapidly from 1167 when Henry II banned English students from attending the University of Paris. In post-nominals, the University of Oxford was historically abbreviated as Oxon. (from the Latin Oxoniensis), although Oxf is nowadays used in official university publications. 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 English universities have many common features and are often jointly referred to as Oxbridge. In addition to their cultural and practical associations, as a historic part of British society, they have a long history of rivalry with each other.