Complex sentence: He rose from private to company sergeant major and "after three years and 334 days in the service, he was commissioned in the field on 9 April 1917" Monks to become "the only Jewish officer in the Brigade of Guards".
Split into simpler sentences: He rose from private to Company Segeant Major and after three years and 334 days in the service, he was commissioned on the field on the 9 April 1917 Monks. He was "the only Jewish officer in the Brigade of Guards".