'Laws made for the purpose of restraining luxury or extravagance, particularly against inordinate expenditures in the matter of apparel, food, furniture, etc' 1
Sumptuary laws were imposed in Ireland by the English at various stages throughout it's medieval and early modern history in an attempt to control the Gaelic Irish. In the 16th century the Lord Deputy Sir John Perrot under Queen Elizabeth I in the 16th century, for the purpose of restraining native Irish dress, banned the wearing of woollen mantles, 'open smocks' with 'great sleeves' (leine), and native headdresses, requiring the people to dress in "civil garments" in the English style.
Going back to the 13th century the English imposed sumptuary laws against their own subjects in Ireland firstly banning the excessive use of fur in the merchant class. The English merchant class that existed at this time had been early Planters but as time passed and England was distracted by foreign disputes these English settlers were left to their own devices in Ireland and began to adopt Irish customs and the Irish language. It's from here that we get the saying "they became more Irish than the Irish themselves". From the Parliament of Ireland in 1297 we get the quote; 'all Englishmen in this land must wear, at least in that part of the head which presents itself to view, the mode and tonsure of Englishmen'. Irish hairstyles, most notably the culan were forbidden. In 1537 another Gaelic hairstyle was banned, the glib, where the hair was shaved above the ears except at the front of the face where it was grown long to cover the eyes. This hairstyle was describes as 'fit masques as a mantle for a thief'.
In the Statutes of Kilkenny in 1366 Englishmen were prohibited from intermarrying with the Irish or adopting the Irish language or Irish customs of dress. Notably in the Parliament in Trim, 1447, it was said that a 'man that will be taken for an Englishman shall have no beard above his mouth.' This was re enforced on various occasions up to the 17th century. The moustache was seen as an extremely Gaelic fashion. Many contemporary illustrations and descriptions of Irish warriors such as Gallowglass and Kern are generally sporting moustaches and over time it became a form of defiance against the English to wear one.
In 1462 a tax was imposed by the Parliament in Dublin on Irish mantles and in 1466 it was decreed that anyone found wearing one was to be fined a sixpence. Also in 1466 it was declared that if a woman wore a saffron smock in Dublin she would be fined a sixpence. The dying of garments in saffron was another particularly Irish custom and it became synonymous with the Gaelic Irish. Henry VIII first banned the use of saffron in Galway in 1536 and then throughout the rest of the country in 1537. He said that it could not be use in any shirts, smocks, head coverings, or linen caps. Ironically in 1577 sufficient amounts of saffron were still being sold on Galway to warrant a tax per pound to help pay for maintenance in the town.
In the 16th century laws were imposed on how many garments people of certain classes could own and of what fabrics and decoration they were to be made of. Henry the VIII's Prohibitive Act of 1537 banned overly voluminous leine which could be no more than 6.4m of cloth, and again banned the wearing of the Irish mantle. (Some leine's were reputed to have been made of up to 32m of cloth before the act was passed).
Over the years various sumptuary laws were passed in Parliaments in London and Dublin in an attempt to bring the Gaelic Irish and the old English Planters under control but as we can see they had to be repeated quite regularly because it seems to be that however hard the English tried to civilize the Irish, they became more and more stubborn in their defiance to the Crown, resulting in certain infamous Irish clothing traditions surviving through many centuries.
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“For can the sword teach them to speak English, to use English apparel, to restrain them from Irish exactions and extortions, and to shun all the manners and orders of the Irish? No it is the rod of justice that must scower out those blots...justice without the sword may suffice to call all those to her presence...to defend the English from all Irish spots, to settle him in the quiet estate they were in before they so degenerated.”
~Lord Chancellor Gerrard to the Privy Council, 1577.
“It will be necessary to call a parliament to enact new statutes for establishing the articles ensuing...Irish habits for men and women to be abolished, and the English tongue to be extended.”
~Sir Henry Sidney, A Discourse for the Reformation of Ireland, 1585.
1 Black's Law Dictionary