The Olomouc Missal @museum.de

So far, you’ve seen mainly forgeries, copies and reproductions, and only a few valuable Cranach originals. But here, in the museum's treasure chamber, you’ll find original works on paper by Lucas Cranach the Elder and the Younger.

This is also where the Foundation’s most valuable exhibit is kept – the Olomouc Missal. This rare missal, which prescribes the course of a mass, was designed to be used in the Olomouc diocese in Moravia. It originated during Cranach's time in Vienna – between 1501 and 1505 – when he made woodcuts for the book printer Johannes Winterburger.

This magnificent edition from 1505 is bound in leather. Twenty small and twenty large figural woodcut initials by Cranach feature on its 288 pages. They’re among the artist’s earliest woodcuts. One half-page woodcut shows a disc that was used to establish the Dominical, or Sunday letter, while another woodcut features the crucifixion of Christ.

In the display case, the book has been opened on the page with the diagram used to establish the Dominical letter – decorated with a magnificent white-line woodcut by Cranach. We’ve also enlarged the image and put it on the wall to give you a better view.

Medieval calendars always included the Dominical, or Sunday letter. It gives the date of the first Sunday in the year. Afterwards, a table was drawn up to assign the seven letters from A to G to the seven days of the week. In 1490 – as you can see in the table – Sunday fell on the 3rd day of the year. So in that year, the Sunday letter was C. You only needed to glance at the matching calendar to see that all the other days of the year marked with a C were also Sundays.

The second circle (working inwards) takes leap years into account. The third circle is used to establish the date of Easter. The fourth, inner circle lists the Roman interest number, which repeats in a 15-year cycle. That’s the day on which taxes came due.