Institutional development of mathematics in Serbia rests on two national institutions: Belgrade Higher School established in 1863, from 1905 the University of Belgrade, and the Serbian Royal Academy founded in 1886, later the Serbian Academy of Sciences and today the Serbian Academy of Sciences and Arts. Dimitrije Nešić, professor of mathematics and rector of the Belgrade Higher School, founded the first mathematics library in Serbia in 1871. In time, as a result of the collaboration between the Academy and the University and overlapping activities, it had become the main place for mathematicians to gather and work and became known as the Mathematical Seminar of the University of Belgrade. The year 1896 is considered to be the year when the Seminar was officially founded and when it began its activities as an institution. Professors Mihailo Petrović and Bogdan Gavrilović, members of the Serbian Royal Academy, were the two people most responsible for its establishing. The period between the two world wars is the most significant period in the development and institutionalization of the activities of the Mathematical Seminar and Petrović's school of mathematics, which represent the root of the overall development of mathematics in Serbia. The Mathematical Institute was founded in 1946 under the authority of the Serbian Academy of Sciences. All Institute achievements and activities -- publishing activities, organization of scientific seminars, introducing young and talented mathematicians to scientific work, improving the education process at the University of Belgrade -- are pointed out. Today, after 70 years, the Mathematical Institute developed into the most significant Serbian institution of mathematics.