When he turned to the study of history, he remarked that he was returning "to an old interest and took up modern history with the idea of seeing how the theory of evolution would appear in human development".
Kada je krenuo na studij povijesti rekao je kako se vraća "starom zanimanju te je uzeo modernu povijest s namjerom da vidi kako bi teorija evolucije izgledala u čovjekovu razvoju".