Complex sentence: Ironically, he failed to predict accurately the date of his own death; although he prophesied that he would die on 17 November, 1961, he did not die until 1 June, 1988, at Cedar-Sinai Hospital in West Hollywood, California.
Split into simpler sentences: Ironically, he failed to predict accurately the date of his own death. Although he prophesied that he would die on 17 November 1961, he did not die until 1 June 1988, at Cedar-Sinai Hospital in West Hollywood, California.