Among the pardoned persons listed in a fiant of 1603 were a group of tradesmen from Gracescastle, now rendered Castlegrace, in the Co Tipperary parish of Tulloghorton. There were two carpenters, a smith, a yeoman and a weaver. The later's names was Dermod m' Philip O Keherne. Kern and kerne according to the Oxford Dictionary derive from ceithearnach, which means "a light-armed Irish foot-soldier"; one of the poorer class among the "wild" Irish, but additionally "a rustic, boor, vagabond".
From this derived surnames O and Mac Ceitearnaigh (descendant, and son of Ceithearnach), variously anglicised O Keherne, O Kerny, Kerne, Keherny, Kerney, Kerns, Kearns, and Kearney, and M'Kehernie, M'Keherne, Keherney, Kerny and Kearney. Kearney is the usual anglicised form of the quite separate names of O/Mac Ceithearnaigh are concealed amidst the evenly disributed 1,173 Kearneys found in current telephone entries south of the Border, and the approximately 280 to its north.
Conor, Tomoltagh, Jordan kewgh, Shane grana, and another unnamed person, all M'Kehernes of Cloynscioke, in the Co Roscommon barony of Ballintober, were among the pardoned in a fiant of 1591. The Tithe applotment books of 1824 note Keherney in the parish of Fethard, and Keherny in the parish of Tubbrid, both in Co Tipperary.
Annala Rioghachta Eireann/Annals of the Four Masters notes the death in 1095 of Cairbre O Ceithearnaigh, bishop, successor of Maedhog at Ferns. That same year was noted for the great fall of snow on the Wednesday after Easter, which killed "innumerable men, fowle and cattle". In 1167 Cineath O Ceithearnaigh, priest at Inis Clothrann (now Inchcleraun in the Co Longford parish of Cashel) died. The second part of Topographical Poems, written by Giolla-na-Naomh O hUidhrin (d. 1420) places O Ceithearnaigh in Munster, probably in west Cork. Woulfe's Sloinnte Gaedheal is Gall says that O Ceithearnaigh, also called Mac Ceithearnaigh, were chiefs of Ciarrai, or Kerry, a district in the barony of Castlereagh, Co Roscommon, but also the name of a west Cork family.
An Advice for Ireland, penned in 1607, contained three seperate recommendations. The first was that His Majesty would "pretend some cause to draw into England such Ireish of note whose Septs or stockes have been factious and nurishers of Rebellion"; the second to force those who did not succumb to such blandishments "to put them selfs in Armes, whereby ye uttermost of theyr malice is discovered: and less dainger is in open Rebell than a secret". And finally: "In Ireland there are certain kinde of swordsmen called kerne: descended from Horseboys, Idle persons and unlawful propigation. They are base, apt to follow factions, and live allwaies by yr spoyle, and will never be brought to other Conformitie there: but if they might be drawne from thence, and imployed to ye planing of Virginia: the Countrie shold be well freed, and tyme elsewhere Eate them oute or amend them. The number of these people in Ireland I suppose will not exceede 7 or 8,000."
One of the great Norman families to come to Ireland was Grace, gaelicised Gras. They were descended from Raymond le Gras who married Strongbow's daughter, and ever since have been associated with Co Kilkenny and adjacent areas. A number of places in the four midland countries of Kilkenny, Carlow, Laois, Kildare and in Tipperary have taken their names from the Grace family: Castlegrace, Grace Castle, Gracewood, Graceland, Grace's Court and Gracefield. Castlecastle, from whence Dermod O Keherne, had been Gracecastell in 1408; gracys castell in 1506; Graciscastell in 1546; Gracecastle in 1562, but had become Castlegrace in 1603.
The Civil Survey 1654-58 notes that the Mannor of Castlegrace was then the property of Thomas Lord Baron of Cahyr, Irish Papist. "Upon the sd lands stands a large stone house, a little castle both covered with thatch, and two turretts within a bawne whereof the sd house castle and turretts are pt all lately rebuilt at the chardge of the Commonwealth, likewise some thacht houses, cabbins and grist mill."
Writing in 1837 about the parish of Tulloghorton, Samuel Lewis's Topographical Dictionary of Ireland notes that a silver mine, which had been worked up till recently was in the townland of Castlegrace. "The ruins of a castle, denominated Castle-grace, consist at present of two towers on the east side, comprising an area of about 40 yards square." As early as 1550 the names of this places has been rendered Caislean an Grasaigh, "Grace's Castle".