late > recent wealthy > [rich] strand > shore

3 Inglorious now lies in senseless swoon,

senseless > unconscious

4 Through heavy stroke of Britomart's hand.

heavy > grievous; grave

5 Which when his mother dear did understand,

dear > dear (if applied to Cymodoc{e"}); grievously, at great cost (if applied to "understand")

6 And heavy tidings heard (where she played

heavy > distressing; grave, grievous

7 Amongst her watery sisters by a pond,