Early Polish Printing pt 2:
A summary of the “Computus” or the calculation by which the date of Easter Sunday is determined i.e. the means to find the date of the first full moon after the vernal equinox. A popular publication in Cracow issued by the major printing houses of the early 16th century, beginning with Jan Haller and Florian Ungler’s editions in 1522. This one was published by Mathiam Scharffenberg in 1534.