The Múrna (Old Irish: Mugdorna) were pushed out of northern Meath sometime after 800 by the Gailenga Mora. The Gailenga left their name in the barony of Morgallion (from Irish: Machaire Gailenga, meaning "the plain of the Gailenga") in northern County Meath. Tribes of the Gailenga Mora were located in the baronies of Morgallion and Lower Kells in county Meath, and the barony of Clankee in County Cavan, in the early eighth century.
In 1172 King Henry II of England granted the Lordship of Meath to Hugh de Lacy to hold as King Murrough O Melaghlin held it. Once established de Lacy proceeded to divide up his newly acquired territory into feudal grants to his chief followers. He granted the territory of the Gaileanga-Mor sept (the lands of Magherigalon, later to be known as the Barony of Morgallion) to Gilbert de Angulo, who had arrived from Wales in 1171. The caput of the barony was at Nobber where de Angulo constructed a Motte close to the site of an earlier ecclesiastical site.
At Knock, in Morgallion barony, is an argillaceous clay deposit containing a portion of iron, which has been adapted for the coarser kinds of earthen-ware.
- Hugh McGough. "Gailenga Mora". Mughdhorna. Retrieved 2007-08-22.
- "Irish local names explained". Library Ireland. Archived from the original on 2007-06-27. Retrieved 2007-08-22.
- "Gilbert de Angulo". The History of the Nangle Family. Archived from the original on 2009-10-23. Retrieved 2007-08-22.
- Lt Col Frank Nangle. "History of the Barons of Navan". A Short History of the Nangle Family. Archived from the original on 2009-10-23. Retrieved 2007-08-22.
- "Meath". Lewis's Topographical Dictionary of Ireland. 1837. Archived from the original on 2007-08-19. Retrieved 2007-08-22.
www.morgallion.com Historical Novel Set in the Barony of Morgallion.