Humpty Dumpty sat on a wall.
Humpty Dumpty had a great fall.
All the king's horses and all the king's men
Couldn't put Humpty together again!

History: From the East Anglia Tourist Board in England:
"Humpty Dumpty was a powerful cannon during the English Civil War (1642-49).
It was mounted on top of the St Mary's at the Wall Church in Colchester defending the city against siege in the summer of 1648. (Although Colchester was a Parliamentarian stronghold, it had been captured by the Royalists and they held it for 11 weeks.) The church tower was hit by the enemy and the top of the tower was blown off, sending "Humpty" tumbling to the ground. Naturally the King's men* tried to mend him but in vain."
* NB: The "men" would have been infantry, and "horses" the cavalry troops.