Answer: The grandfather repeats a line about a war he knows nothing about.
In this poem, the grandfather is telling his granddaughter about a famous battle, the battle of Blenheim. As he describes it, he keeps repeating that the battle was a "famous victory." He seems to admire the battle, and to believe it to have been remarkable. However, the irony is that, at the end, it becomes clear that the grandfather does not know why the battle was fought or what came out of it.
