1911 Encyclopædia Britannica, Volume 26… (1911)
“ THOMOND, EARL AND MARQUESS OF, Irish titles borne by the great family of O’Brien, the earldom from 1543 to 1741 and the marqucssate from 1800 to 1855. Thomond, or Tuaidh-Muin, was one of the three principalities of Munster, forming the northern part of the province. Its earls were descended from Turlough O’Brien (c. 1009–1086) , king of Munster, and through him from the celebrated king of Ireland, Brian Boroimhe. Turlough's descendants, Conchobhar O’Brien (d. 1267) and Brian Ruadh O’Brien (d. 1276) , kings of Thomond, were both typical Irish chieftains. ”
