 While he was sojourning in Berlin during the summer of 1886, he and Elisabeth both resolved to divorce their respective spouses and to marry each other.Ardenne, however, saw his secretly harboured suspicions confirmed when he located the hiding place of the letters which his wife and Hartwich had been exchanging over the course of several years.Thereupon he filed for divorce and challenged his rival to a duel, an event upon which massive media coverage had been centred before it took place on 27 November 1886.