Covers a number of varied topics on the subject matter.
Such as the increasing interest in British history as a topic for painting. And increasing interest in making it look right. A watershed moment was when West insisted on doing the Death of General Wolfe in -- well, normal clothes, such as were worn at the time, which was, after all, well within a normal lifespan.
Scott's enormous influence. The paintings on scenes from his works helped normalize everyday historical scenes.
A section on the people who actually went out and dug up the medieval illuminations and the like to get the costumes right, and the subtle changes introduced by how they redrew them. And the artists whose work can be traced, figure by figure, to the drawings that were published. (I know a reenactor who found that particularly interesting, because these drawings are also an influence there.)
I particularly liked the section where he treated common themes that painters used, and the moral lessons they drew from them. Because of course, working from British history didn't mean it wasn't still the genre history painting, full of grave themes and heroic example.