Tycho Brahe in front of his house in Copenhagen. Tycho Brahe left Hven in 1597, bringing some of his instruments with him to Copenhagen, and entrusting others to a caretaker on the island. Shortly before leaving, he completed his star catalogue giving the positions of 1,000 stars. After some unsuccessful attempts at influencing the king to let him return, he finally acquiesced to exile, but he wrote his most famous poem "Elegy to Dania" in which he chided Denmark for not appreciating his genius. The instruments he had used in Uraniborg and Stjerneborg were depicted and described in detail in his book
Tycho Brahe in 1580, taught Count Wilhelm of Kassel and his astronomer Christoph Rothmann to build copies of Brahe's instruments without permission from Brahe. In turn, Craig, who had studied with Wittich, accused Brahe of minimizing Wittich's role in developing some of the trigonometric methods used by Brahe. In his dealings with these disputes, Tycho Brahe made sure to leverage his support in the scientific community, by publishing and disseminating his own answers and arguments. When Frederick died in 1588, his son and heir Christian IV was only 11 years old. A regency council was appointed to rule for the young prince-elect