1 Which when Satyrane beheld, in haste 2 He left his captive beast at liberty, 3 And crossed the nearest way, by which he cast
cast > contrived; resolved
4 Her to encounter, ere she passed by:
encounter > go to meet; face as an adversary
5 But she the way shunned nathemore for-thy,
But > (Pleonastic) nathemore for-thy > not at all for that reason (i.e. she did not alter her course because of that)
6 But forward galloped fast; which when he spied, 7 His mighty spear he couched warily,
couched warily > {Carefully lowered and placed in its rest, ready for attack}
8 And at her ran: she, having him descried, 9 Herself to fight addressed, and threw her load aside.
addressed > prepared