Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. Cambridge University Press, a department of the university, is the world's oldest publishing house and the second-largest university press in the world. The university also operates eight cultural and scientific museums, including the Fitzwilliam Museum, as well as a botanic garden. Cambridge's libraries hold a total of around 15 million books, eight million of which are in Cambridge University Library, a legal deposit library.
In the year ended 31 July 2016, the university had a total income of £1.64 billion, of which £462 million was from research grants and contracts. The central university and colleges have a combined endowment of around £6.3 billion, the largest of any university outside the United States. The university is closely linked with the development of the high-tech business cluster known as "Silicon Fen". It is a member of numerous associations and forms part of the "golden triangle" of leading English universities and Cambridge University Health Partners, an academic health science centre.
As of September 2017, Cambridge is ranked the world's second best university by THE World University Rankings, the world's fourth best university by three other ranking tables, and no other institution in the world ranks in the top 10 for as many subjects. The university has educated many notable alumni, including eminent mathematicians, scientists, politicians, lawyers, philosophers, writers, actors and foreign Heads of State. As of 2017, 116 Nobel Laureates,10 Fields Medalists, 6 Turing Award winners and 15 British prime ministers have been affiliated with Cambridge as students, faculty or alumni.
By the late 12th century, the Cambridge region already had a scholarly and ecclesiastical reputation, due to monks from the nearby bishopric church of Ely. However, it was an incident at Oxford which is most likely to have formed the establishment of the university: two Oxford scholars were hanged by the town authorities for the death of a woman, without consulting the ecclesiastical authorities, who would normally take precedence (and pardon the scholars) in such a case, but were at that time in conflict with King John. The University of Oxford went into suspension in protest, and most scholars moved to cities such as Paris, Reading, and Cambridge. After the University of Oxford reformed several years later, enough scholars remained in Cambridge to form the nucleus of the new university. In order to claim precedence, it is common for Cambridge to trace its founding to the 1231 charter from King Henry III granting it the right to discipline its own members (ius non-trahi extra) and an exemption from some taxes (Oxford would not receive a similar enhancement until 1248).
A bull in 1233 from Pope Gregory IX gave graduates from Cambridge the right to teach "everywhere in Christendom". After Cambridge was described as a studium generale in a letter by Pope Nicholas IV in 1290, and confirmed as such in a bull by Pope John XXII in 1318, it became common for researchers from other European medieval universities to visit Cambridge to study or to give lecture courses.