In 1175 as a result of the Treaty of Windsor between Henry II of England and Rory, High King of Ireland, Ireland became subject to the English Crown. English kings ruled through the appointment, first of Justicars and later of Lords Deputy, and Lords Lieutenants. In 1177 Henry II created his son John, "Dominus Hiberniae" Lord of Ireland, at the same time two Normans, Robert Fitzstephen and Milo de Cogan were granted the Kingdom of Cork between them, and Philip de Braose was granted the Kingdom of Limerick. Later in history, the more famous and much married Henry VIII was the first to use the title of King of Ireland.
Our Irish and European ancestors grew up in an environment that was for the most part decided for them. Their social and economic standing in Irish society was determined by the existing rulers. These rulers [Barons] were absolute and had rights far beyond what exist today. The right of gallows as an example, enabled the local Baron to ride into town and hang anybody he wanted, whenever he wanted. That, along with other less intrusive rights made for a society that was restrictive at best.
Although, in 1377 the doctrine of barony by tenure seems to have been accepted, it was nearly a century later before the first official creation of an Irish Baron, that of Baron Trimleston in 1462. Not long afterwards this was followed by the creation of the first Irish Viscount in 1478 (Gormonston).
Ireland has 331 Baronies in 32 Counties. The Barony of Orhera, County Armagh, Ulster and the Barony of Drumahaire, County Leitrim, Connacht offer two good examples of the typical Irish Barony: Orhera or Drumahaire. The Barony of Orhera's older name being Orier Bar and its current modern name being Orior Lower. Drumahaire's older name being Drumagheire.
There are three distinct types of Feudal Barons in British and Irish
history:
Baron by Tenure
Baron by Writ
Baron by Letters Patent