Diarmait mac Conaing (died 786) was a King of Brega from the Uí Chonaing sept of Cnogba (Knowth) of the Síl nÁedo Sláine branch of the southern Ui Neill. He was the son of Conaing mac Amalgado (died 742) and brother of Congalach mac Conaing (died 778), previous kings. He ruled from 778 to 786.
The Kings of Brega were rulers of Brega, a petty kingdom north of Dublin in medieval Ireland.
Knowth is a Neolithic passage grave and an ancient monument of the World Heritage Site of Brú na Bóinne located 8.4 km west of Drogheda in Ireland's valley of the River Boyne. It is the largest passage grave of the Brú na Bóinne complex. It consists of a large mound and 17 smaller satellite tombs. The mound is about 12 metres (40 ft) high and 67 metres (220 ft) in diameter, covering roughly a hectare. It contains two passages placed along an east-west line and is encircled by 127 kerbstones, of which three are missing, and four badly damaged.
Síl nÁedo Sláine[ˈsʲiːlʲ ˈnaiðo ˈslaːnʲe] are the descendants of Áed Sláine, son of Diarmait mac Cerbaill. Part of the Southern Uí Néill—they were the kings of Brega—they claimed descent from Niall Noígiallach and his son Conall Cremthainne.
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The high king Donnchad Midi (died 797) had campaigned against Leinster in 780 and then made peace. The next year in 781 the Battle of the Rig was fought between the Síl nÁedo Sláine and the Uí Garrchon branch of the Laigin and their king Cú Chongalt was slain. [1] Donnchad had subdued Brega in 778 and the annals do not mention whether this campaign versus the Uí Garrchon was part of Donnchad's campaign or an act of defiance by the men of Brega or simply a border warfare with no connection. The campaign is significant in that both septs of the Síl nÁedo Sláine, both the Uí Chernaig and the Uí Chonaing of north Brega, participated together. These two septs had been fighting for much of the eighth century. Diarmait and his cousin Conaing mac Dúngaile led the Uí Chonaing sept.
Donnchad mac Domnaill, called Donnchad Midi, was High King of Ireland. His father, Domnall Midi, had been the first Uí Néill High King from the south-central Clann Cholmáin based in modern County Westmeath and western County Meath, Ireland. The reigns of Domnall and his successor, Niall Frossach of the Cenél nEógain, had been relatively peaceful, but Donnchad's rule saw a return to a more expansionist policy directed against Leinster, traditional target of the Uí Néill, and also, for the first time, the great southern kingdom of Munster.
In 786 Febordaith, the abbot of Tuilén was killed apparently by the Síl nÁedo Sláine. [2] The high king Donnchad Midi revenged this by attacking and defeating the forces of the Síl nÁedo Sláine at the Battle of Lia Finn or Tuilén and Diarmait was slain along with his kinsman Conaing mac Dúngaile [3] Both septs, the Uí Chernaig and the Uí Chonaing, again participated.
