Model UN began as a series of student-led Model League of Nations simulations. The first simulations were called “international assemblies”, the first of which was held at Oxford University in November 1921, with the potential first ever simulation being on 12 November 1921. Following several simulations in Oxford, Mir Mahmood, the president of the first Oxford International Assembly, traveled to Harvard in 1922 to help spread this idea further.
He advocated for the League of Nations, and inspired the Harvard Liberal Club to create the first American International Assembly held at Harvard University in 1923. The Oxford International Assembly ceased to exist in the following years, but the Harvard International Assembly remained strong, and has since encouraged the development of these simulations worldwide.