The National and Kapodistrian University of Athens (Greek: Εθνικόν και Καποδιστριακόν Πανεπιστήμιον Αθηνών, Ethnikón kai Kapodistriakón Panepistímion Athinón), usually referred to simply as the University of Athens (UoA), is a public university in Athens, Greece. It has been in continuous operation since its establishment in 1837 and is the oldest higher education institution in the modern Greek state. Today it is the second biggest university of Greece in number of students (following the Aristotle University of Thessaloniki), with more than 50,000 undergraduate students. In 2012 it was ranked in the positions 501–550 among the best universities in the world, according to the index of QS World University Rankings, as well as according to the evaluation of Academic Ranking of World Univers