In Process Citation

We report on a newly discovered letter by Christoph Rothmann, dated July 1st 1584, and addressed to Johann Ernst of Anhalt. The letter supports the earlier assumption that Johann Ernst recommended Rothmann to Landgrave Wilhelm of Hesse, as Rothmann asks for Johann Ernst's help on the matter in this new source. More importantly Rothmann refers to his attempts to make Copernicus' calculations compatible with the Ptolomean model, which demonstrates that already at this stage of his career he was working on such a compromise, and not only after being influenced by Raimarus Ursus or Tycho Brahe, as has been argued by some authors.