model for people at other institutions to look to, than are the independent colleges of Oxford and Cambridge". This has been widely followed in the US, where the colleges at universities such as Harvard, Yale and Princeton are entirely owned by the central university. Some universities, such as the University of Otago in New Zealand, Durham University in the UK and the University of Pavia in Italy have a mix of independent and university-owned (or, in the case of Pavia, state-owned) colleges. In many collegiate universities, following the pattern of Oxford and Cambridge, membership of a college is obligatory for students, but in others it is either not necessary or only necessary for students in particular faculties, e.g. at the University of Toronto, where the colleges are all associated with the Faculty of Arts and Sciences. Non-centralised teaching collegiate universities Sometimes, as noted above, referred to as federal universities, these are universities where the teaching function is entirely carried out by constituent colleges, which will often have their own faculties and departments. This is represented by examples such as Oxford and Cambridge up to the mid 19th century, the University of Wales from 1893 to 2007, and the University of London from 1900. The level of legal separation – e.g. whether the colleges are separate corporate bodies – varies between universities. As the colleges are primarily teaching institutions, they may not always be residential communities and many are effectively universities in their own right. Some colleges are part of loose federations that allow them to exercise nearly complete self-governance, and even (as in the case of colleges of the University of London) award their own degrees. Other colleges are not legally separate from their parent university, e.g. the University of the Arts, London (UAL) in the UK and many state university systems in the US. In some US state systems, a "flagship campus" may be identified – often the original campus of the system – which is considered (either officially or informally) to stand above the other campuses in the system (e.g. University of Wisconsin–Madison, University of Colorado Boulder). Some universities may have centralised teaching but also have colleges that do not access that centralised teaching. Historically, this was the case at Durham University for the medical school and Armstrong College in the late 19th and early 20th century (prior to the formation of a true federal university in 1908)