In a word, the historical scholar and quite specifically the medievalist, has a twofold duty: one to his own speciality, to his own chosen field of scholarship, where he can justifiably claim expertise, and the other to society which after all maintains him and which makes it possible for him to apply himself with singular zeal to his own research. But this duty to society makes it imperative for him to return to it the fruits of his own research work and learning by putting his specialist work into a broader perspective. In many instances he will do this all the better and with greater success if he tries to apply all his methods, techniques and topics to periods antecedent to and succeeding those which originally fired his research enthusiasm.

Walter Ullmann, The Future of Medieval History
Inaugural lecture in the University of Cambridge,
delivered 6 November 1973