between 1596 (Sidney Sussex College) and 1800 (Downing College), which allows the colleges to be distinguished into two groups according to foundation date: the 16 "old" colleges, founded between 1284 and 1596, and the 15 "new" colleges, founded between 1800 and 1977. The oldest college is Peterhouse, founded in 1284, and the newest is Robinson, founded in 1977. Homerton, which was first founded in the eighteenth century as a dissenting academy (and later teacher training college), attained full college status in 2010. Restrictions on entry All 16 of the "old" colleges and 7 of the 15 "new" ones admit both male and female students as both undergraduates and postgraduates, without any age restrictions. Eight colleges restrict entry by sex, or by age of undergraduates, or admit only postgraduates: King's originally only admitted boys from Eton College until 1865. Murray Edwards and Newnham admit only women. Lucy Cavendish admitted only women until 2021; Lucy Cavendish admitted only mature students, i.e. aged 21 or older until 2020, or postgraduates until 2021; Clare Hall and Darwin admit only postgraduates; Hughes Hall, St Edmund's and Wolfson admit only mature students (defined as aged 21 or older) or postgraduates. No colleges are all-male, although most originally were. Darwin, founded in 1964, was the first mixed college, while in 1972 Churchill, Clare and King's colleges were the first previously all-male colleges to admit women, whilst King's formerly only accepted students from Eton College. The last all-male college to become mixed was Magdalene, in 1988. In 1973 Hughes Hall became the first all-female college to admit men, and Girton first admitted men in 1979. Newnham also places restrictions on the admission of staff members, allowing only women to become fellows of the college. Murray Edwards does not place this restriction on fellows. Architectural influence The Cambridge and Oxford colleges have served as an architectural inspiration for Collegiate Gothic architecture, used by a number of American universities including Princeton University and Washington University in St. Louis since the late nineteenth century. List of colleges There are also several theological colleges in the city of Cambridge (for example Ridley Hall, Wesley House, Westcott House and Westminster College) that are affiliated with the university through the Cambridge Theological Federation. These colleges, while not officially part of the University of Cambridge, operate programmes that are either validated by or are taught on behalf either of the university or of Anglia Ruskin