The Muintir Eolais of Conmaicne Réin, were nobles of Gaelic Ireland. For seven hundred years from the 8th century, they lived and ruled an area roughly conterminous to present-day south County Leitrim. Their territory comprised the lands named Maigh Nissi and Maigh Rein, today the baronies of Leitrim and Mohill respectively. The Mag Raghnaill, O'Mulvey, and Mac Shanley rule became increasingly fragmented throughout the 16th century. The tuath of the Muintir Eolais collapsed with Irish defeat in the nine years war, and became largely forgotten with the English occupation of Ireland.