Words of warning

From The Whig Interpretation of History, Butterfield's must-read 1931 historiographical essay:

[T]he chief aim of the historian is the elucidation of the unlikenesses between past and present . . . It is not for him to stress and magnify the similarities between one age and another, and he is riding after a whole flock of misapprehensions if he goes to hunt for the present in the past.
— Herbert Butterfield

Or, in the oft-repeated saw of L.P. Hartley, "The past is a foreign country; they do things differently there." For an example of the "flock of misapprehensions" a present-minded investigator can run into, see my Historical Movie Monday post on Kingdom of Heaven.