Norman mercenaries land at Bannow Bay in Leinster, marking the beginning of the Norman invasion of Ireland.

The Normans were a population arising in the medieval Duchy of Normandy from the intermingling between Norse Viking settlers and locals of West Francia. The Norse settlements in West Francia followed a series of raids on the French northern coast mainly from what is now Denmark, although some also sailed from Norway and Sweden. These settlements were finally legitimized when Rollo, a Scandinavian Viking leader, agreed to swear fealty to King Charles III of West Francia following the siege of Chartres in 911, leading to the formation of the County of Rouen. This new fief, through kinship in the decades to come, would expand into what came to be known as the Duchy of Normandy. The Norse settlers, whom the region as well as its inhabitants were named after, adopted the language, religion, social customs and martial doctrine of the West Franks but their offspring nonetheless retained many of their traits, notably their mercenary tendencies and their fervour for adventures. The intermixing between Norse folk and native West Franks in Normandy produced an ethnic and cultural "Norman" identity in the first half of the 10th century, an identity which continued to evolve over the centuries.

Bannow is a village and civil parish lying east of Bannow Bay on the southwest coast of County Wexford, Ireland.

Leinster is one of the four provinces of Ireland, in the southeast of Ireland.

The Anglo-Norman invasion of Ireland took place during the late 12th century, when Anglo-Normans gradually conquered and acquired large swathes of land in Ireland over which the monarchs of England then claimed sovereignty. The Anglo-Normans claimed the invasion was sanctioned by the papal bull Laudabiliter.