This is a perpetual calendar printed in Germany. It is decorated with borders containing geometric patterns, ornate floral motifs, and acanthus. Beneath the heading ‘Kalendar’ is the name of the month, which can be changed by moving a tab up or down on the verso of the page. The days of the week are listed at left: ‘Montag’ to ‘Sonntag’ (Monday to Sunday) with thirty-one days of the month arranged in numerical sequence on the grid. The weekdays are also moveable when a second tab on the verso is pulled up or down to fix in place the correct day. A perpetual calendar is valid for many years, and can allow for the calculation of the day of the week for a given date in the future. This example is a seven-day one-month calendar where the tables for days and months slide against each other, so that aligning the two scales with one another reveals specific dates via a window mechanism.