What is the writing on this woodcut? Nul on Urlaub doesn't seem to make sense, aber mein Deutsch is sehr schlecht.
"Nüt on Ursach" (Nichts [ist] ohne Ursache. Nothing [happens] without a reason/cause.)
It's a motto from the popular book "Das Narrenschiff" (ship of fools) by Sebastian Brant that was first published in 1494.
Prints of the book from 1506 and 1512 show the motto prominently on the title page. The original print from 1494 does not have the motto on the title page, but only in the editor's sign by Johann Bergmann von Olpe, who also used it in his sign on other works he edited (sometimes in Latin as nihil sine causa). So I'm not sure about the original relation between the motto and Brant's text.