He ruled for thirty years: he transformed and rebuilt Montecassino, starting with the abbey church, commissioned works of art and books, and increased the monastery’s economic well-being. The monk Leone Marsicano, who lived during Desiderius’s time and was therefore an ‘eyewitness’ to his achievements, describes him in Book III of the ‘Chronica Monasterii Casinensis’ as an abbot who distinguished himself not only for the restoration and construction of buildings, but above all for his commitment to the preservation and dissemination of knowledge.
A particularly evocative image is the ‘Scena di dedica’ (Dedication Scene) contained in the manuscript Vat. Lat. 1202 [https://digi.vatlib.it/view/MSS_Vat.lat.1202]. Desiderius dons a large red cloak. This garment is his due because he is cardinal of the Roman church of Santa Cecilia in Trastevere and papal legate for Southern Italy. He is depicted handing the book to St. Benedict, along with other codices, placed at his feet, with gem-studded bindings. In the lower part of the image, there are also churches, lakes and walled cities, which the abbot offers to the saint. Two captions accompany the scene and explain the meaning and purpose of the offering: ‘Together with these buildings, accept, O Father, the many splendid books. I bring you lands and lakes. May you bring me Paradise’ (‘Cum domibus miros plures pater accipe libros. Rura laco presto. Caeli michi prestitor esto’).
Desiderius was the mastermind behind a true ‘golden age’ for Montecassino. Under his leadership, the monastery enjoyed a period of great splendour and became one of the main centres of culture and art in Europe.