The source Google book contains images and OCRs of a 1843 transciption of the original manuscripts by King Dom Duarte, beginning 1400. The transciption collects two books of Duarte de Portugal: Bem cavalgar (this one) and Leal conselheiro; the second one will be used into a separate Galeria: page.
After some test, a conservative approach (t.i. saving all diacritics and any other features of source text) have been applied (May 2010).
See also the alternative edition: Galeria:Bem cavalgar (1842).djvu.