As first created in 1836, the University of London was an examining board for its affiliated colleges (initially only University College London and King's College London, often referred to as the 'founding colleges'), including a number of Catholic institutions and dissenting academies whose students could not take degrees at Oxford, Cambridge or Durham. This system continued until 1858, when University of London examinations were thrown open to all students with the establishment of the external degree system. The University of London later became a federal university in 1900. By 1858, the following institutions (as they are given in the 1858 charter) had been recognised as affiliated colleges: