From > [From becoming the] of > [of the]

3 Her faithful guard removed, her hope dismayed, 4 Herself a yielded prey to save or spill.

spill > destroy

5 He, now lord of the field, his pride to fill,

He, now lord > (Or: He now, lord)

6 With foul reproaches and disdainful spite

disdainful > hateful; angry; contemptuous

7 Her vilely entertains and, will or nill,

entertains > treats will or nill > willy-nilly, will or will not

8 Bears her away upon his courser light: