Until Chamberlain's death, he and Wilhelm had what the American historian Geoffrey Field called "a warm, personal bond", which was expressed in a series of "... elaborate, wordy letters, full of mutual admiration and half-baked ideas". The Wilhelm–Chamberlain letters were full of "the perplexing thought world of mystical and racist conservatism". They ranged far and wide in subject matter: the ennobling mission of the Germanic race, the corroding forces of Ultramontanism, materialism and the "destructive poison" of "Judentum" were favorite themes. Other subjects often discussed in the Wilhelm-Chamberlain letters were the dangers posed to the "Reich" by the "Yellow Peril", "Tartarized Slavdom", and the "black hordes".