The Humboldt University of Berlin (German: Humboldt-Universität zu Berlin, abbreviated HU Berlin) is a university in the central borough of Mitte in Berlin, Germany. It was established by Frederick William III on the initiative of Wilhelm von Humboldt as the University of Berlin (Universität zu Berlin) in 1809, and opened in 1810, making it the oldest of Berlin's four universities. From 1828 until its closure in 1945, it was named Friedrich Wilhelm University (German: Friedrich-Wilhelms-Universität). In 1949, under Eastern Bloc rule, it was reopened and for this occasion renamed "Humboldt University of Berlin" (Humboldt-Universität zu Berlin). The university is divided into nine faculties, including its medical school shared with the Free University of Berlin, has a student enrollment of around 32,000 students, and offers degree programmes in some 189 disciplines from undergraduate to postdoctorate level. Its main campus is located on the Unter den Linden boulevard in central Berlin. The university is known worldwide for pioneering the Humboldtian model of higher education, which has strongly influenced other European and Western universities, and the university has been widely called "the mother of all modern universities." As of 2017, the Humboldt University of Berlin has been associated with 55 Nobel Prize winners, and is considered one of the best universities in Europe as well as one of the most prestigious universities in the world for arts and humanities. It was widely regarded as the world's pre-eminent university for the natural sciences during the 19th and early 20th century, and is linked to major breakthroughs in physics and other sciences by its professors such as Albert Einstein. Former faculty and notable alumni include eminent philosophers, artists, lawyers, politicians, mathematicians, scientists, and Heads of State.