348 For well he knew, his Muse would soon be tired

tired > attired, adorned

349 In her high praise, that all the world admired. 350 351 Yet as Achilles, in those warlike frays, 352 Did win the palm from all the Grecian peers:

palm > {Leaf or "branch" of palm tree: symbol of victory; hence:
victory}
peers > rivals; nobles

353 So Spenser now, to his immortal praise, 354 Has won the laurel quite from all his feres.

laurel > {Crown of laurel leaves for supreme poet or victor} feres > companions, peers

355 What though his task exceed a human wit,

What though > Inasmuch as wit > mind; wit

356 He is excused, sith Sidney thought it fit.

sith > since