After having been one of the most important Fathers of the Church, Jerome becomes indeed the subject of an intense investigation. By a research in ecclesiastical and monastical libraries, a Benedictine monk known as Adrianus Brielis increases to 200 items the corpus of epistles written by Jerome.
This outstanding work is classified thematically by Brielis and published by Schoeffer in 1470 in two successive editions, incorporating new discoveries and significant reworks in the second edition.
The first workshops of movable type printing in southern Germany are inseparable from the industry of the copyists but also of the illuminators. Once printed, the specimens were illuminated by hand in more or less extent to be marketed at various prices.
On July 7, 2010, Christie's sold as lot 10 for £ 940K including premium a deluxe copy printed in Mainz in 1470 by Schoeffer of the Letters (Epistolae) of St. Jerome (Hieronymus) gathered by Brielis. It is now estimated € 600K for sale in Paris Hôtel Drouot by OVA - Aristophil operated by Aguttes on June 16, lot 26.
It is a large-size book on vellum 48 x 33 cm. This extensively illuminated copy is in a remarkable original condition, still in its binding in two volumes made in period in Erfurt.
This copy from the first edition has been extensively amended in handwriting to add the modifications in preparation for the second edition, providing a fair view of the concurrent practice of editing and printing for that operation. For sure the expensive double printing including red ink for the rubrication did not invite for a scrap of the obsolete copies.
The discussion above is mostly based on my 2010 post.