Tycho died on 24 October 1601 in Prague, eleven days after suddenly becoming very ill during a banquet. Toward the end of his illness he is said to have told Kepler "Ne frustra vixisse videar!", "Let me not seem to have lived in vain.
For hundreds of years, the general belief was that he had strained his bladder
. It had been said that to leave the banquet before it concluded would be the height of bad manners, and so he remained, and that his bladder, stretched to its limit, developed an infection which later killed him. This theory was supported by Kepler's first-hand account.
Recent investigations have suggested that Tycho did not die from urinary problems but instead from mercury
poisoning: extremely toxic levels of it have been found in his hair and hair-roots. Tycho may have poisoned himself by imbibing some medicine containing unintentional mercuric chloride
impurities, or may have been poisoned.
One theory proposed in a 2005 book by Joshua Gilder and Anne-Lee Gilder, suggests that there is circumstantial evidence that Kepler murdered Brahe; they argue that Kepler had the means, motive, and opportunity, and stole Tycho's data on his death.
According to the Gilders, they find it "unlikely"
Tycho could have poisoned himself since he was an alchemist known to be familiar with the toxicity of different mercury compounds.
Another theory is proposed by Peter Andersen, professor of German Studies at the University of Strasbourg
. Andersen discovered the 600-page diary of Count Erik Brahe, a distant Swedish cousin of Tycho. He suggests Erik murdered Tycho, by order of King Christian IV of Denmark
, who suspected that Tycho had had an affair with his mother Sophie
In 2009, a group of cons ervators, chemists and physicians plan to open the vault and perform a forensic analysis on the body.
Tycho Brahe's body is currently interred in a tomb in the Church of Our Lady in front of Týn
, in Old Town Square
near the Prague Astronomical Clock