A certain Valentin von Spangenberg, employed also by Frederick II, appears to have been responsible for the construction of the dam for Tycho Brahe's paper mill. Here the astronomer produced paper for his scientific works. A votive stone with an inscription celebrating the project had during the years become very worn, but by various means it has become possible to reconstruct the text with great certainty. The stone was split at a certain time, but renewed investigation has revealed hitherto unobserved details of the stone.