Oh yes, Kepler and Brahe. They are the central characters in “Heavenly Intrigue”, by Joshua and Anne-Lee Gilder, a dual biography which concludes that Brahe’s unexpected death in his early 50s came about as a result of mercury poisoning (this from 21st century DNA studies of Brahe’s hair), and that only Kepler, then an assistant to Brahe, had the knowledge of the effects of mercury, access to Brahe’s laboratory, where mercury was kept for various experimental and medical reasons, and a motive, to steal Brahe’s drawings of the solar system, which were kept under strict control by his employer.
Did Brahe die of mercury poisoning? I guess so. Did Kepler kill him? I don’t see that the evidence points here, at least not as clearly as the authors do. Kepler was a very difficult man, paranoid and angry. Brahe was the opposite – he got along with everyone, and was clearly an optimist under all circumstances. Brahe was the mentor, and Kepler probably didn’t think a mentor was necessary. He must have clearly felt that Brahe was, in fact, holding him back, both by keeping him occupied unsatisfactorily and keeping from him the secrets he needed to proceed.
Upon Brahe’s death, Kepler did steal his papers, that much is true. And he did use them to go on and conduct his own, successful, and creative experiments. No one, not even the authors who accuse Kepler of murder, detract from his accomplishments.