Tycho Brahe days days in the year pregnant with misfortune, wherefore in Denmark, up to this very day, the laboring class call such days on which they happen to meet with some unfortunate accident, Tycho Brahe's days." In his travelogue "A Poet's Bazaar", Hans Christian Andersen alludes to the fact that Tycho Brahe died in exile in Prague, observing that "Denmark owns not even his dust; but the Danes mention his name in their bad times, as if a denunciation proceeded out of it: 'These are Tycho Brahe's days!' say they." However, no mention of the Tycho Brahe days is actually found in
Tycho Brahe "Rudolphine Tables". Also at the court in Prague was the mathematician Nicolaus Reimers (Ursus), with whom Tycho had previously corresponded, and who, like Tycho, had developed a geo-heliocentric planetary model, which Tycho considered to have been plagiarized from his own. Kepler had previously spoken highly of Ursus, but now found himself in the problematic position of being employed by Tycho and having to defend his employer against Ursus' accusations, even though he disagreed with both of their planetary models. In 1600, he finished the tract "Apologia pro Tychone contra Ursum" (defense of Tycho against Ursus). Kepler had great respect for