World-renowned Renaissance astronomer Tycho Brahe died on 24 October 1601, after 11 days of illness. Several conspiracy theories regarding his death have been aired, the first shortly after his death by William Shakespeare in the play Hamlet, published in 1603. A key factor in the still lively debate is whether he was administered mercury—as medicine by his own hand, or as poison by an unfriendly hand. In 2010, Brahe's grave was reopened and samples of his bones, hair, teeth and the textiles were procured and analysed. Here, we present evidence that Brahe was not administered lethal doses of mercury.