In January 1469, the accounts of Duke Charles the Bold of Burgundy record a payment to the scribe Nicolas Spierinc for having written "some prayers for my lord." Seven months later, the same accounts note a payment to the illuminator Lievin van Lathem for twenty-five miniatures plus borders and decorated initials in the same manuscript. In this seminal study, the late Antoine de Schryver argues that the documents refer to the prayer book of Charles...