139 historical is not such as of a historiographer. For a

historical > [writing historical or epic works] such as > [like that] historiographer > chronicler, historian

140 historiographer discourses of affairs orderly, as they were

orderly > in sequence

141 done, accounting as well the times as the actions, but a poet

well > [much] times > dates

142 thrusts into the middest, even where it most concerns him,

middest > middle [of the story; cf. in medias res (Horace, Ars Poetica 148-9)]

143 and there, recoursing to the things forepassed, and divining

recoursing > returning forepassed > [which have already happened]