This is a memorial to "William's true and gallant knight -- Schomberg, the bold and brave!" He'd had a "bright career ... But at the Boyne, for ever famed, He fell beside the wave"
For background on the Boyne, and on Schomberg, see the notes to "The Battle of the Boyne (I)." It might be noted that, although Schomberg had had an excellent career, his performance in Ireland was not very energetic (he was, after all, in his seventies); it was his failure to win the Irish campaign which forced William of Orange to come himself and fight at the Boyne. Some of Schomberg's problems were not his fault -- but many were; he made a hash of his logistics, resulting in his force suffering many useless casualties. - RBW