The grand old Duke of York, was that a specific battle , does anyone know ?
According to that great source of all wisdom

Wikipedia ... Prince Frederick, Duke of York commanded the army during the 1793 Flanders Campaign in the French Revolutionary Wars and the hill was Cassell. However this theory is disputed as the rhyme seems to predate this, though not quite in the same form:
"The King of France with forty thousand men,
Came up a hill and so came downe againe"
was written around 1642.
So, I guess no one really knows
