Mourne is a barony in County Down

County Down

-Cities:*Belfast *Newry -Large towns:*Dundonald*Newtownards*Bangor-Medium towns:...

, Northern Ireland

Northern Ireland

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. It lies in the south-east of the county, with the Irish Sea

Irish Sea

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 to its east. It is bordered by two other baronies: Iveagh Upper, Lower Half and Iveagh Upper, Upper Half to the north and west. Mourne gets its name from the Múrna (Old Irish: Mughdorna), a people who hail originally from a territory of the same name in modern County Monaghan

County Monaghan

County Monaghan is a county in Ireland. It is part of the Border Region and is also located in the province of Ulster. It is named after the town of Monaghan. Monaghan County Council is the local authority for the county...

.

The Múrna

The Múrna are described as being a powerful people in the "archaic" period and possibly either being a pre-Celtic or very early Celtic people who may have been rulers of Ulster before the ascendancy of the Ulaidh. Early genealogists would claim that they descend from Mughdhorn Dubh, a son of Colla Menn, however this has been rebuked as a figment of imagination and as politically fashionable at the time. Indeed Mighdorna is listed as being one of the territories conquered from the Ulaidh by the Three Collas with Colla Menn taking possession of Mughdorna. The O'Hanratties are stated as having anciently possessed this territory.

Bairche

Bairche is the ancient name of the Mourne territory and originally the Mourne Mountains had also been named Beanne-Boirche ("Boirche's peaks"). According to the Dinnsenchus they were named after a shepherd called Boirche who herded on the mountains the cattle of Ross, son of Imchadh, a king of Ulster in the third century. The Dinnsenchus states that his favourite look-out point was the highest peak in the mountain range, hence why the mountains received the name.

According to the Annals of Ulster around 1165 the Ua Eochadha asked Muircertach Ua Lochlainn, High-King

High-King

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 of Ireland, that the kingship of Ulidia

Ulidia

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 be given to Eochaidh Mac Duinnsleibhe. In return they gave pledges for everyone in Ulidia to Ua Lochlainn as well as many of their treasures. Mac Duinnsleibhe also gave the territory of Bairche to Ua Lochlainn, who then gave it to Donnchadh Ó Cearbhaill (O'Carroll) of Louth

County Louth

County Louth is a county of Ireland. It is part of the Border Region and is also located in the province of Leinster. It is named after the town of Louth. Louth County Council is the local authority for the county...

, lord of Airgialla

Airgíalla

Airgíalla or Airgialla was the name of an Irish federation and Irish kingdom which first formed around the 7th century...

.

Migration of the Múrna to Bairche

By the 11th and 12th centuries the Múrna in Monaghan had become subordinate to the Ui Chremthainn, ruled by the powerful Ó Cearbhaill (O'Carroll). The last king of Mughdorna, Maolruanaigh Ó Machainen (O'Machoiden), is recorded in the Annals of Ulster as being slain in 1110.

In the latter half of the 12th century, a group of the Múrna emigrated from Cremorne to south Down where they settled in Bairche to form a new kingdom. It is suggested that Donnchadh Ó Cearbhaill, being lord of Airgialla which included the original territory of the Múrna, having just received the territory of Bairche may have transplanted them to the area to reinforce his control over it. They would rename Bairche and its mountains after their tribal name, hence the present-day names of Mourne and the Mourne Mountains.

O'Dugan lists O'Machoiden as being rulers in the 12th century of Mourne in County Down.

Annals of Ulster

The Annals of Ulster state for Bairche:

• 601.1 - An earthquake in Bairche.
• 611.1 - The army of the Ulaid was struck by terrible thunder in Bairche.
• 674.1 - The killing of Congal Cennfhatar son of Dúnchad, king of Ulaid. Béc of Bairche killed him.
• 679.3 - The battle of Fínnechta against Béc of Bairche.
• 707.6 - The pilgrim's staff assumed by Béc of Bairche.
• 712.7 - The Ulaid were overthrown and Dubthach son of Béc of Bairche fell therein.
• 714.7 - A battle between two sons of Béc of Bairche and Bresal's son, king of Uí Echach, and the victors therein were Béc's sons.
• 718.2 - Béc of Bairche dies.
• 730.6 - Oitechde son of Baithectde, Blamac's son, and Aengus son of Béc of Bairche, rested.
• 753.13 - A whale was cast ashore in Bairche in the time of Fiachna son of Aed Rón, king of Ulaid. It had three gold teeth in its head, each containing fifty ounces, and one of them was placed on the altar of Bennchor this year, that is, in AD 752.
• 1109.9 - A slaughter was inflicted on the Uí Méith, including their king, i.e. Goll Bairche, and some of the men of Fernmag fell by the Uí Bresail and the Uí Echach.
• 1165.10 - ...and he [Mac Duinnsleibhe] gave Bairche to Ua Lochlainn [and] Ua Lochlainn gave it to [Donnchadh] Ua Cerbaill...