988 AD. 105.Brian Boru as the Heberian Dal gCais King of Thomond / Northern Munster and 41st King of Cashel / Munster carried out a raid from his fleet situated on Loch Ree, in Midhe / Meath in Northern Leinster, which was the territory of *104.Malachy 11 / Mael Sechnaill who was now the Gaelic Milesian Heremonian Ui Cobhthaigh Dal Cuinn "southern" Ui Niaill Clann Cholmain 174th King of Ireland.

989 AD. *104.Malachy 11 the "southern" Ui Niaill 174th King of Ireland besieged the Munster Province and for a few years the "southern" Ui Niaill and the Heberian Dal gCais were to engage in ongoing conflict, which was to also have an effect on the nearby Connacht Province and Southern Leinster as 105.Brian Boru's overall power structure continued to grow.

 995 AD. *105.Brian Boru as the Heberian Dal gCais 41st King of Munster had previously received support from *104.Malachy 11 the "southern" Ui Niaill 174th King of Ireland against the continual Viking threat, but he now decided to organize Ireland as a whole under his own leadership and *104.Malachy 11 naturally feeling ever threatened by *105.Brian Boru's  improving position, decided to uproot one of the two sacred trees / bile at Magh Adhair (The Meadow of the Sacred Oaks) the Crowning place of the Heberian Dal gCais / Dalcassian Kings of Thomond / Northern Munster located near Clooney / Quin in Co. Clare, and he then cut it into pieces. This desecration had occurred while *105.Brian Boru was away bringing the Heremonian Ui Laoghaire Ui Connla kingdom of Ossory / Co. Kilkenny in the south - west of Southern Leinster, once again, under his submission in Mogha's Half. Because of *104.Malachy's sacrilege of Magh Adhair, 105.Brian Boru had lost respect for him and as a result he besioeged his "southern" Ui Niaill territory in Co. Westmeath in the south - west of Northern Leinster, which was in reality an attack on the High Kingship of Ireland.

997 AD. *104.Malachy 11 the Gaelic MIlesian Herremonian Dal Cuinn Clann Cholmain "southern" Ui Niaill 174th King of Ireland was forced to divide Ireland up with *105.Brian Boru and there was then peace among the Irish Tuaths / Family regions and an arrangement was made near Clonfert in Co. Galway in the Connacht Province where they both held a meeting, that *104.Malachy 11 would control the north of Ireland  (Conn's Half / Leth / Cuinn) and *105.Brian Boru the south of Ireland (Mogha's Half / Leth Mogha) against the continuing Viking menace.

999 AD. By now all had submitted to *105.Brian Boru except the Heremonian Ui Cobhthaigh Dal Cuinn "northern" Ui Niaill, the Vikings under Sitric in Dublin, and Sitric's maternal uncle, 108.Mael Morda the Heremonian Ui Laoghaire Ui Lughaidh Cu Corb Ui Dunlainge Ui Faelain 45th King of Leinster, who continued to carry out personal attacks in his own territory in Southern Leinster, (which endeared him to no one subject to his rule there) and *105.Brian Boru then came up against a revolt there in Southern Leinster that was backed by Sitric and the Vikings in Dublin who also objected to submitting to him, so he marched on Southern Leinster and defeated them at Glenn Mamain in Co. Dublin in the north - east of Southern Leinster and then marched onto Dublin itself where he stayed over for a month to secure it also. 108.Mael Morda the 45th King of Leinster, along with Sitric his half -Viking nephew, who was the Viking King of Dublin, had to accept *105.Brian Boru as their overall King in Mogha's Half, and they gave over hostages. Feeling more secure now *105.Brian Boru decided to challenge *104.Malachy 11, for the overall High Kingship of Ireland, which would allow him to try and bring about total unity in Ireland, *105.Brian Boru called on those he now saw as his allies to support his push for the High Kingship of Ireland. He also drew support from Dublin, Southern Leinster and some of the other Viking warriors and their Chieftains, and together with the Septs in the Munster Province, the kingdom of Ossory, and the Septs in the south of the Connacht Province he laid siege to *104.Malachy 11 the "southern" Ui Niaill 174th King of Tara / Ireland at his fortress in the Midlands / Midhe / Meath / Northern Leinster. While the battle was occurring a section of *104.Malachy's warriors were defeated, so he decided to withdraw, and he then requested that his Heremonian kinsmen the "northern" Ui Niaill ijn the Ulster Province come to his aid and give him their support against *105.Brian Boru, but it was not forthcoming as Aed O Niall the Heremonian Dal Cuinn "northern" Ui Niaill Cenel nEogain King of Aileach stated categorically that, "He was not willing to go into battle against the Heberian Dal gCais over sovereignty." *104.Malachy 11 then decided it was best to concede to *105.Brian Boru without incurring further bloodshed, who then became the Gaelic MilesianHeberian Dal gCais 175th High King of Ireland.