The Veronense (Vetustissimi Libelli Romani Veronae = The Verona Collection of Ancient Roman Libelli) is the so-called "sacramentarium Leonianum" or "Sacramentarium Veronense". It is a collection of ancient Roman liturgical prayers used in Rome during the fourth up to the sixth centuries As a collection, it was compiled at the end of the sixth century or in the beginning of the seventh century. The actual manuscript of the collection was discovered by Scipione Maffei in 1712 (not in 1713) in Verona Chapter Library, Since then up to the present, the study on the manuscript manuscript and the content of the prayers has been undertaken In this booklet, some main confusing information concerning the unique manuscript kept in the Verona Chapter Library are going to be clarified particularly 1) the date of the discovery of the manuscript, 2) the name of the manuscript, 3) the date and author of the prayers, 4) the structure and content of the Veronense. Ihis clarification is helpful in grasping the value of the manuscript and the importance of these ancient Roman liturgical prayer as a Christian "euchological deposit".