The Hexaemeron of St Ambrose

'Hexaemeron' means the period of six days, specifically the six days of creation of which the book of Genesis speaks. In early Christian and medieval times, the biblical account was believed to have been revealed to the author--sometimes said to be Moses--by a vision. The 4th-century bishop of Milan, St Ambrose, wrote several commentaries on Genesis, among them his Hexaemeron. It was an important book to medieval theologians because, among other things, it contained a store of information about the natural world. This copy of the Hexaemeron belonged to the cathedral priory of Rochester, where it may have been written by the precentor (choir master) named Humfrey.

At the top of the first page, the inscription in red identifies the book and quotes Genesis 1:3-4 (creation of light and dark on the first day). In the lower margin the inscription identifies the book as belonging to the cloister of Rochester, given by the cantor.