This is a classical Al Stewart historical folk-rock song, though more folk than rock. Richard Grenville was born in 1542, and after a distinguished career as a soldier and explorer, he was appointed Vice Admiral of the Navy. In 1591, he sailed for the Azores in pursuit of Spanish treasure but found himself outnumbered when his ship the Revenge
became separated from the rest of the fleet. After fighting fifteen Spanish ships all evening and night, the Revenge
was surrendered by his crew against his wishes. Mortally wounded, Grenville was taken prisoner and died aboard one of the enemy ships aged only forty-nine.
His heroic death was celebrated by Alfred Lord Tennyson in the poem The Revenge - A Ballad of the Fleet
; this ballad though is written through the eyes of one of his disillusioned crew, beginning and ending with the line "Go and tell Lord Grenville that the tide is on the turn". Check out a photo of Lord Grenville
. (thanks, Alexander Baron - London, England)