Mesrop Mashtots ' Matenadaran Institute of Ancient Manuscripts in Yerevan , Armenia , is one of the richest depositories of manuscripts and books in the world . The Mesrop Mashtots Institute of Ancient Manuscripts ( Mesrop Mashtots ' i anvan hin dzeá agreri institut ) , commonly referred to as the Matenadaran , is an ancient manuscript repository located in Yerevan , Armenia . It holds one of the world 's richest depositories of medieval manuscripts and books which span a broad range of subjects , including history , philosophy , medicine , literature , art history and cosmography in Armenian and many other languages .