Early years
Brian Boru is one of the twelve sons of King Thomond Cennétig mac Lorcáin (died 951). King of Thomond, died in a battle with the Vikings in 951, near Limerick. The new king of Thomond was the eldest son of Cennétig. In 953, hostile clans killed the current king and one of his brothers. Mathgamain, the third son of Cennétig, avenged the death of his elder brothers and took the crown of Thomond. In 960, Mahoun, the eldest son of Cennétig and brother of Brian Boru, accepted the crown of Munster, and Brian became the ruler of Thomond in northern Munster.
In 962, Brian Boru, with a handful of followers (200 people) from his clan Dal Qais, went to the mountains of Claire and began a partisan war against the Vikings from Limerick. In 968, the Dal Qais clan went on a campaign to Cashel, where, after the Vikings were defeated from Limerick, Matgamine was declared king of Munster, and King Ivar of Limerick (Dane) was banished from Ireland by Mahun. In 969 Ivar returned to Limerick and became the ruler of the large islands on the r. Shannon. In 976, the king of Munster Matgamine mac Cennétig ( 960 – 976 ), the elder brother of Brian Boru, was meanly killed by Ivar of Limerick, who was in collusion with Eoghanahtah. After that, the entire clan Dal Qais fell under the influence of Brian Boru.
King of Munster
In 978, Brian Boru killed King Munster Maelmoad Mac Bran ( 976 – 978 ). Brian unleashed a series of wars against Connacht, Mide, Leinster, and Brayfne. In 984, Brian Boru became the ruler of Lech Mogi, southern Ireland. The conquered tribes of Brian imposed a tribute to the cattle, which was called “Borom” (that is, tax, in modern pronunciation of Bor), from which originated his nickname.
Strengthening ties with the Viking Dublin, Brian Boru gave his daughter Slane to marry Sitrik the Silkbred (son of Olav Kvaran and Gormleit).
In 999, the battle of Glenmama took place. Brian Boru drove the army of Danes and Leinsters, led by King Maelmore, who, after the defeat, hid in a yew tree, from which Brian Bor’s son Moorhad himself had taken it.
High King of Ireland
Having subjugated all the pyatina, by 1002, Brian Boru became the Supreme King of Ireland. Interestingly, in Arma’s book, he is not called “ Ard Rí ”, that is, “High King”, but “ Imperator Scottorum ” – literally “Emperor of the Scots ” (“ Scottorum” was a common toponym of Ireland by later ancient authors; Hybernia, common in classical antiquity changed “Scotia Major”, while the lands of modern Scotland began to be called “ Scotia Minor ” instead of the name Caledonia).