The crafts of the healer and the herbalist were well established in the Gaelic tradition. When the Tuatha De Danann were preparing themselves for battle with the Fomorians, Dian Ceacht, the Tuatha's doctor, went to Lusmagh to collect herbal cures, as we read in Diolaim Luibheanna (Nicholas Williams).
Williams adds that anybody interested in native cures will be disappointed in the medical books compiled by the Irish families who practised healing. These books were nothing more than translations of books in Latin, written in England and on the Continent.
Among the Irish medical families Williams mentions are Muintir Dhoinnshleib he, Clann Mhic Lea, and Muintir Ici. The first of these has been anglicised Dunlevy, the second made MacClay/MacAlea (lia, healer), and the last Hickey (ici, physician).
The Cashin family were originally hereditary physicians in Laois, and among the tituladoes listed in The Census of Ireland 1659 was Dr Conly Cassin, gent, Aghkippo in the barony of Ossory. Others were Morgan Cashin, gent., Rahincullen, and Morgan Cashin (the same?), and Palmershill in the parish of Aghaboe.
Cassin and Cashin were among the principal Irish names in the Co Tipperary barony of Eliogurty and Ikerrin, and in the Laois baronies of Maryborough and Ossory. The above Dr Cassin, author of a medical tract in Latin in 1667, is listed as "Cassin Conly of Offaly", publisher of a small volume in 1667 vindicating the views on fever of Dr Willis, in John F. Fleetwood's The History of Medicine in Ireland.
The Irish for (Mac) Cashin/Cassin, according to Sean de Bhulbh's Sloinnte na hEireann/ Irish Surnames is Mac Caisin (cas, bent, or pleasant). De Bhulbh notes that there seemed to be confusion with O Caisin, which he says relates to Munster.
The late 14th century Topographical Poems informs that O Caisin was lord of the Soghain. Of the seven Soghain, six were in Ui Maine - parts of Counties Roscommon, Galway, Clare, and Offaly, and one in Meath.
Mac Cashins were found in Co Kildare as early as 1304, and in 1313 in north Co Tipperary. The Irish Fiants of the Tudor Sovereigns (1521-1603) list the 1585 pardons of Thomas boy m'Cashin and Ilan Cashane, surgeons in Co Laois. In 1601 Owen oge m'Owen O Cashine in the Co Laois barony of Cullenagh, and Thomas O Cassin of Tulla, Co Tipperary, were among the pardoned.
The Mac Cashins were Irish Papist proprietors in Co Laois in 1640. The O Doyne (O Duinn) Manuscript notes that in 1607 Miagh McCassin, of the Barriemore in the barony of Ossory, a tenant of O Duinn, had major holdings outside Iregan (later the Co Laois barony of Tinnahinch).
A Minister's Money Account for Clonmel, Co Tipperary in 1703 contains the name of Margaret Casseene, while a rental account of 1726 notes Hugh Cassane in Ahena and Drumshinnagh, Co Mayo.
Taylor's & Skinner's 1778 Maps of the Roads of Ireland shows Casson Esq at Sheffield near Portlaoise, Co Laois, and the 1814 Directory lists Matthew Cassan, Esq, at Sheffield, with Stephen Cassan Esq, at Capponellan, Co Laois. Sheffield House was in the townland of Cappoley, parish of Kilcolmanbane, according to O'Hanlon's Queen's County. Capawley (?Ceap Amhlaidh) was an earlier spelling.
Owners of Land of One Acre and Upwards (1876) shows a 10-acre Casson holding in Co Dublin, with four Cassin holdings in Co Laois. Patrick Cassin, Knockheel, had 10 acres; Matthew, America, had 22 acres; Joseph Cassan, Ballyknockan, parish of Kilcolmanbane, had 124 acres, and Matthew S. Cassan, Sheffield House, had 1,979 acres.
O'Hanlon says that Cassan in Co Laois was a corruption of De Cassagne, a family formerly resident at Caen in France. At the Revocation of the Edict of Nantes, De Cassagne fled to Flanders, thence to England, later taking part in the Battle of the Boyne.
A Captain Sheffield who had acted as aide de camp to the Duke of Buckingham when Lord Lieutenant of Ireland obtained an estate in the townland of Cappoley. Here he built Sheffield House, and married a Miss Cassan, or de Cassagne, ". . . and thus we get the present-day patronymic of `Cassans of Sheffield'." The family owned property in other townlands, and gave magistrates, deputy lieutenants, and high sheriffs to the county.
Telephone directories south of the Border contain 121 Cashin entries, 57 Cassin, and 21 Cashen - half of each being in the 05 area of south Leinster and Co Waterford. There are 11 McCashin and two Cassin entries north of the Border.
Saint Colman Ban is recognised as the patron of Kilcolmanbane - Cill Cholmain Ban, "the church of Colman Ban".