Editing Brian Boru (section)

===Ulster campaigns===
Ulster's geography presented a formidable challenge. There were three main routes by which an invading army could enter the province, and all three favoured the defenders. Brian first had to find a means of getting through or around these defensive [[choke point]]s and then he had to subdue the fiercely independent regional kings of Ulster. It took Brian ten years of campaigning to achieve his goal, which, considering that he could and did call on all of the military forces of the rest of Ireland, indicates how formidable the kings of Ulster were.<ref name=":5" />

Brian received naval support throughout his northern campaigns from [[Sigtrygg Silkbeard]] of Dublin. Silkbeard was eager to enact revenge against the Ulaid for when they refused to assist him after he was forced out of his [[kingdom of Dublin]] by Brian following the Battle of Glenmama in 999, forcing Silkbeard to return to Dublin and submit to him.<ref name=":5" />{{Failed verification|date=July 2020}}

Brian was also greatly helped by the fact that two years before his first campaign in Ulster, in the year 1003, the brutal battle of Craeb Telcha had taken place between the Northern Uí Néill and the Ulaid, in which the king of the [[Branches of the Cenél nEógain|Cenél Eoghain]] and of the Uí Neill was killed and most of the Ulaid [[Royal descent|royal bloodline]] was wiped out, with the Uí Néill gaining victory. This then led to a bloody [[war of succession]] within and between the clans of the Ulaid, and together with further attacks from the Uí Néill, which led to the kingdom's being severely weakened. Brian accepted the submission of the Cenel Eoghain king in 1005 and later accepted the submission of many of the Ulaid clans at a sacred Ulaid site, Emain Macha.<ref name=":5" />

However [[Flaithbertach Ua Néill|Flaithbertaigh Ua Néill]], the new king of the Northern Uí Néill and of the Cenél Eoghan, although having already submitted to Brian, was apparently unwilling to accept fully the High King's authority, and was quite rebellious. He was known for his continued aggression towards his neighbours despite previously accepting Brian's rule. In 1005, after Brian had departed Ulster, he attempted to exert his overlordship over the Ulaid, and seemingly wanted to punish them for submitting to Brian, to which the Northern Uí Néill were vehemently opposed. He attacked the kingdom, killing several kings and princes of the Ulaid. He also took several hostages.<ref name=":5" />

This caused Brian to return in 1006 and again in 1007 to deal with Flaithbertach. On the latter occasion, he removed the hostages of the Ulaid from Flaithbertach's custody and took them into his own custody (according to the [[Annals of Inisfallen]], Brian had to take the hostages forcefully).{{citation needed|date=August 2020}} Flaithbertaigh again submitted, and also married one of Brian's daughters, Bé Binn.<ref name=":5" />

Despite this, Brian continued to be troubled by the rebellious Flaithbertaigh. In the year 1009, Flaithbertaigh blinded and then executed the [[Kings of Tír Chonaill|king of the Cenél Chonaill.]] Later that year he would also launch raids in the [[Midlands Region, Ireland|Midlands]] going as far south as the [[River Boyne]]. This led to Brian's return to Ulster yet again, this time taking hostages from the Cenél Eoghain back to his home province, finally gaining the proper submission of Flaithbertaigh.<ref name=":5" />

Flaithbertaigh would then take part in campaigns against the Cenél Chonaill, the final kingdom yet to submit to Brian, in the year 1011 alongside Brian's sons [[Murchad mac Briain|Murchad]] and [[Domhnall mac Briain|Domnall]]. However, they were unsuccessful in gaining the submission of the Cenél Chonaill. Brian then personally proceeded to lead a second invasion later that year, this time successfully subjugating and receiving the submission of the Cenél Chonaill. While Flaithbertaigh would continue attacking the Ulaid and Cenél Chonaill in late 1011 and in 1012, for the time he was no longer of any threat to Brian.<ref name=":5" />

Throughout his campaigns in the province, it was once again Brian's coordinated use of forces on land and at sea that allowed him to triumph; while the rulers of Ulster could bring the advance of Brian's army to a halt{{citation needed|date=September 2021}}, they could not prevent his fleet from attacking the shores of their kingdoms. Once Brian entered the province of Ulster, he systematically defeated each of the regional rulers who defied him, forcing them to recognise him as their overlord.

It was during this process that Brian pursued an alternative means of consolidating his control, not merely over the province of Ulster, but over Ireland as a whole. In contrast to its structure elsewhere, the [[Christianity in Ireland|Church in Ireland]] was not centred around [[diocese]]s and [[archdiocese]]s, but rather around [[monastery|monasteries]] headed by powerful abbots who were members of the royal dynasties of the lands in which their monasteries resided. Among the most important monasteries was [[Armagh]], located in the Province of Ulster.

Brian's advisor, [[Maelsuthain O'Carroll]], documented in the ''[[Book of Armagh]]''{{dubious|date=September 2024}} that, in the year 1005, Brian donated 22 ounces of gold to this monastery and declared that Armagh was the religious capital of Ireland, to which all other monasteries should send the funds they collected. This was a clever move, for the supremacy of the monastery of Armagh would last only so long as Brian remained the High King. Therefore, it was in the interest of Armagh to support Brian with all their wealth and power.

Brian is not referred to in the passage from the ''[[Book of Armagh]]''{{dubious|date=September 2024}} as the {{lang|mga|Ard Rí}}—that is, High King—but rather he is declared {{lang|la|Imperator Scotorum}}, 'Emperor of the Gaels'.<ref>{{cite web| url = https://www.tcd.ie/news_events/articles/crowning-of-irelands-last-scottish-high-king/| url-status = dead| archive-url = https://web.archive.org/web/20191031062115/https://www.tcd.ie/news_events/articles/crowning-of-irelands-last-scottish-high-king/| archive-date = 2019-10-31| title = Crowning of Ireland's Last, Scottish High King - Trinity News and Events}} {{Webarchive|url=https://web.archive.org/web/20201112025128/https://www.tcd.ie/news_events/articles/crowning-of-irelands-last-scottish-high-king/ |date=12 November 2020 }}</ref>

Though it is only speculation, it has been suggested that Brian and the Church in Ireland were together seeking to establish a new form of kingship in Ireland, one that was modelled after the kingships of England and France, in which there were no lesser ranks of regional kings—simply one king who had (or sought to have) power over all others in a [[unitary state]]. In any case, whether as high king or emperor, by 1011 all of the regional rulers in Ireland acknowledged Brian's authority. No sooner had Brian achieved this before it was lost again.{{Citation needed|date=August 2022}}