In 1899 Davis published "Balliol College", a work in the College Histories series, and in 1900, "Charlemagne", in the Heroes of the Nations series, as well as articles in the "English Historical Review" in 1901. In 1903 he published the article "The Anarchy of Stephen's Reign" in the same journal, which presented the idea that the use of the term 'waste' in the Pipe Rolls indicated a much wider devastation resulting from the Anarchy than had been thought, fuelling the belief that a great anarchy occurred during Stephen's reign, although the 'waste' theory was later discredited. His first widely regarded book was "England under the Normans and Angevins", published in 1905, it became a standard authority and reached a tenth print edition in 1930. It was, however, his only substantial contribution to narrative medieval history. In 1911 he wrote the summary "Medieval Europe", in the Home University Library series, but from 1905 was more focused on editorial work, preparing an edition of Benjamin Jowett's translation of Aristotle's "Politics", a revision of William Stubbs' "Select Charters" and starting the calendar of royal charters, "Regesta regum Anglo-Normannorum".