630 631 Who ever gave more honourable prize

prize > prize; plunder

632 To the sweet Muse, than did the martial crew; 633 That their brave deeds she might immortalize

That > [In that]
brave > brave; splendid

634 In her shrill trump, and sound their praises due?

trump > trumpet-note

635 Who then ought more to favour her than you, 636 Most noble lord, the honour of this age, 637 And precedent of all that arms ensue?

precedent > pattern, model
arms ensue > seek after feats of arms; hence: follow a military
career

638 Whose warlike prowess and manly courage, 639 Tempered with reason and advisement sage

advisement > advice; prudence, consideration