Close to end of the mediaeval Serbian state, in the period of Despot Stеfаn Lаzаrеvić, in the first half of the 15th century, Serbia saw a real flourish of culture and art, particularly in literature. Manuscripts were copied at monasteries all over (as there were no printing presses yet) and the most important school of scribes was at the Manasija (Resava) Monastery, so in the scholarly circles today it is called the Resava School. The school was managed by Constantine Philosopher (should not be confused with St Cyril), who introduced new rules in writing the Serbian Slavic language, since in the meantime, the old way of writing, previously introduced by St Sаvа, was made a mess. So all the new books were copied in a new, standardised way, a norm called the Resava School.
Маnаsiја or Rеsаvа Monastery near Dеspоtоvac
Dеspоt Stеfаn Lаzаrеvić, Constantine Philosopher