The Gaelic-Irish Lordship of Kerslawny (ard tiarna-rank) is the noble title that attaches to the head of the MacCarthy Mór sept known as Sliocht Cormaic of Dunguile. Kerslawny was created in the 15th century as an appanage of the royal house, by then-King of Desmond, Tadhg na Mainistreach Mac Carthaigh Mór (r. 1390/2 – 1428), for his second son, Cormac (d.1467). Kerslawny is the anglicisation of the Gaelic-Irish "cois leamhna," meaning "beside the (River) Laune." This area, near present-day Killarney, in County Kerry, Ireland, was the original territory of the sept.