There are several stories and rumors concerning the death of Hugh de Lacy, the first Norman Lord of Meath.
Norman view of warfare (from the Bayeux Tapestry)
The less-colorful tale holds that he died in 1186 after being hit by falling masonry while inspecting work at Durrow. The more-colorful and nationalistic version credits a young stone mason with an opportunistic ambush. While inspecting work on the former abbey at Durrow — once the foremost early Irish university in the early days of the Brehon laws — de Lacy was distracted and bending over to peer at some stonework. A young stone mason, a local man, pulled a battle ax from beneath his tunic and quickly cut the lord’s head from his body. The mason then escaped into nearby woods, and presumably was a hero to the native Irish.
De Lacy’s body then became a literal bone of contention between the natives and the Norman forces, and it was almost a decade later, 1195, before the Normans finally secured his remains and removed them to Bective Abbey, where his body was finally laid to rest. His head was later brought to Dublin and interred with his wife in the Abbey of St. Thomas.
But things still may not be as simple as they appear. Hugh was rumored to have ordered a crown and been making plans to declare himself King of Ireland at the time of his death — introducing the possibility that his assassin may not have been an Irish rebel at all, but was possibly acting on Henry II‘s orders.
With this rumor in mind, King John’s alarm at seeing Hugh’s son Walter harboring enemies of the crown in 1210, which motivated John’s marching on Trim at the head of his army, is a little more understandable. You can read John’s action as decisively moving against a potential rival, and less as the act of an insecure king. John may have felt the possibility of a rival Norman king setting himself up in Ireland was once again in danger of becoming reality, and acted quickly to nip that eventuality in the bud.
Two decades after his death, the specter of Hugh de Lacy still seems to have cast a long shadow across the Irish Sea.