Books of hours or personal prayer books were one of the most lavishly illuminated groups of medieval religious manuscripts. Their history began in the mid-13th century and continued for about 350 years. There is an artistically and technically excellent book of hours in the collection of the Department of Manuscripts and Rare Books at the University of Latvia Academic Library (DMRB ULAL). This example is described and analysed in the article, offering also its attribution. It was possible to put forth a hypothesis about the manuscript’s place of origin as well as the artist involved. The article focuses on the author’s assumption that the manuscript was made in Rouen, the capital of Normandy in France at the workshop of Master of the Échevinage de Rouen not before the 1470s. In order to attribute the book of hours at the ULAL, the original’s artistic finish, type of writing and arrangement of text in this manuscript has been analysed. Important were the typological and comparative methods of art-historical research as well as stylistic and iconographic analysis. Dealing with the technical execution, the author has considered codicological factors. To establish the place of origin and use of the book of hours, the textual content of the calendar, litany and canonical hours of prayer was analysed and it pointed towards a concrete province. The book of hours at the ULAL consists of 120 parchment pages. The manuscript is in French and Latin. Its textual contents consist of a calendar, fragments of gospels, Hours of the Virgin, the Seven Penitential Psalms, litany, the Hours of the Cross and Office for the Dead. Two significant Marian prayers – Obsecro te and O intermerata – are omitted from the manuscript. Analysis of the Hours of the Virgin and litany proved that the ULAL copy was intended for use in the Rouen diocese. In addition, the structure of the calendar and included saints testify that this book of hours was meant for mass consumption and was not a private commission.