Sentence:  [...] His ſtarrie Helme unbuckl'd ſhew'd him <WSD>prime</WSD> / In Manhood where Youth ended ; by his ſide / As in a glittering "Zodiac" hung the Sword, / Satans dire dread, and in his hand the Spear. 
Meaning of the word marked with <WSD> tags:  Early; blooming; being in the first stage.