A history of Ireland in 100 objects Strongbow's tomb, 12th century

After the English king Harold Godwinson was defeated by the invading forces of William the Bastard, duke of Normandy, at the Battle of Hastings in 1066, his royal banner was taken to Dublin by his fleeing sons.

It ended up in the hands of the high king, Toirrdelbach Ua Briain. The image of the Irish king flaunting the banner of a defeated English sovereign has a tragicomic irony.

There is little sense that Irish rulers, in the decades after 1066, fully understood the implications of William’s victory. The Normans were ruthless, thorough and efficient conquerors. Their own origins were in the Viking terrorisation of France that forced the Frankish monarchy to cede them control of Normandy. In England, they mixed extreme violence with cold calculation. During the so-called Harrying of the North in 1069-70, the Normans destroyed food stocks to create a murderous famine. But their operation was mostly a classic case of what historians call elite transfer, with 5,000 families taking ownership of English estates without disturbing the underlying economic structures. This elite was emphatically a military one: the heavily armoured Norman knight, virtually fused with his huge armoured horse into a terrifying machine, was a product of both great wealth and of highly specialised training.

“The Normans,” wrote one medieval chronicler, “are good conquerors; there is no race like them.” It was inevitable that, having consolidated their rule in England and subdued Scotland and Wales, these good conquerors would look to Ireland.

Successive attempts to establish an effective unitary Irish kingdom had failed; the annalists had a stock formula for the chief ruler: “high king with opposition”. As early as 1155, the Anglo-Norman king Henry II discussed a possible invasion of Ireland at the Council of Winchester. As it happened, internecine warfare allowed an opportunist lord, Richard de Clare, whom Henry had deprived of his title of earl of Pembroke, to beat him to the punch.

In 1166, would-be high king Ruaidrí Ua Conchobair defeated and banished the Leinster overlord Diarmait Mac Murchada. Diarmait offered his allegiance to Henry II and received permission to recruit allies in Wales.

Diarmait returned from Wales in 1167 with a small force of Flemings under Richard fitz Godebert and reclaimed part of his kingdom. More Anglo-Norman adventurers then arrived to support Diarmait, with Robert fitz Stephen, Hervey de Montmorency and Maurice de Prendergast helping him take Wexford.

But the most significant arrival was that of de Clare, known in Irish history by his nickname Strongbow, who captured Waterford in August 1170 and married Diarmait’s daughter Aífe. Strongbow went on to take Dublin and fought alongside Diarmait until the latter’s death, in 1171.

Strongbow summed up the qualities of the Anglo-Norman elite: its energetic opportunism, military prowess and acquisitive efficiency. He died in Dublin in April 1176. The plain, almost blunt monument that stands over his grave may or may not be a representation of Strongbow. His original monument was, as an inscription recalls, “broken by the fall of the roof” in 1562 and “set up again”. But Strongbow’s most important monuments were to prove much more enduring.

Where to see it Christ Church, Christchurch Place, Dublin 8, 01-6778099, christchurch dublin.ie