Clàrsach Scots Gaelic, Cláirseach Middle Irish are the Gaelic words for 'a harp'. Scottish Gaelic ( Gàidhlig) is a member of the Goidelic branch of Celtic languages. Middle Irish is the name given by historical philologists to the Goidelic language used from the 10th to 12th centuries it is therefore a contemporary The harp is a Stringed instrument which has the plane of its strings positioned perpendicular to the soundboard. The word clarsach is used in Scottish English and the word cláirseach is used in Irish Language to refer to a variety of small Irish and Scottish harps. Scottish English is the variety of English spoken in Scotland, also called Scottish Standard English. Irish (ga ''Gaeilge'' is a Goidelic language of the Indo-European language family originating in Ireland and historically spoken by the Irish. The harp is a Stringed instrument which has the plane of its strings positioned perpendicular to the soundboard.
The use of this word in English, and the varieties of harps that it describes, is very complex and often causes arguments or disagreements between different groups of harp-lovers.
The Irish form of the word is Cláirseach; this word has an overlapping but much smaller usage in English. Irish (ga ''Gaeilge'' is a Goidelic language of the Indo-European language family originating in Ireland and historically spoken by the Irish.
By and large the word Clàrsach in English, is equivalent to the term Irish harp, the former being preferred in Scottish contexts and the latter in Irish contexts.
The precise Gaelic term for the harp of the Gael is clàirseach Ghàidhealach (Sc. )/cláirseach Ghaelach (Ir. ), meaning Gaelic harp.
Clàrsach is the (Gd.) originally Clàir Shioleach or willow board   and later as Cláirseach in (Irish) versions, attested in written sources from the 14th century. Scottish Gaelic ( Gàidhlig) is a member of the Goidelic branch of Celtic languages. Irish (ga ''Gaeilge'' is a Goidelic language of the Indo-European language family originating in Ireland and historically spoken by the Irish. An older word is cruit, 
The early history of the triangular frame harp in Europe is contested. The origins of the triangular frame harp are lost in the mists of time However the oldest authentic harps to survive are of Gaelic provenance: the Trinity College Harp preserved in Trinity College Dublin, and the Queen Mary Harp and the Lamont Harp in the National Museum of Scotland, Edinburgh. The Trinity College harp is a medieval Musical instrument currently displayed in the long room at Trinity College Dublin. The Queen Mary Clàrsach na Banrìgh Màiri or Lude Harp, is a Scottish Clarsach currently displayed in the National Museum of Scotland The Lamont Harp, or Clàrsach Lumanach (also known as the Caledonian Harp or Lude Harp) is a Scottish Clarsach currently displayed in the National All three are dated approximately to the 15th century and are considered to have been made in Argyll in South-West Scotland 
The characteristic features of the historical clarsach or Irish harp are its strings of metal wire, usually brass but possibly also gold and silver. These are attached to a massive soundbox typically carved from a single log of willow, a reinforced curved pillar and a substantial neck, flanked with thick brass cheek bands. Usually played with the fingernails, it produced a brilliant ringing sound.
Three medieval Gaelic harps survived into the modern period, two from Scotland (the Queen Mary Harp and the Lamont Harp) and one in Ireland (the Trinity College harp, sometimes romantically called the Brian Boru harp). Artistic evidence from study of the decorative designs on the instruments implies that all three were probably made in the western Highlands.  Opportunities for the Trinity harp to travel across the Irish Sea from Scotland into Ireland were, many, varied, and extremely colourful.  There are at least 15 other early Gaelic harps dating from post medieval times to c. 1800; though most are in Ireland and are usually assumed to be Irish, many have no provenance.
Until the end of the Middle Ages the historical clarsach or Irish harp was the highest status musical instrument of both Scotland and Ireland, and harpists were amongst the most prestigious cultural figures amongst Irish chiefs and Scottish kings and earls. In both countries, the harpist enjoyed special rights and played a crucial part in ceremonial occasions such as coronation and poetic recital.
The main function of the historical clarsach or Irish harp in medieval Scotland and Ireland seems to have been playing to accompany the recitation of bardic poetry in Gaelic or Irish.
Especially popular in 16th and 17th century English courts, the historical clarsach or Irish harp was played all over Europe. It was developed in the 17th century and made by Mack Helvin. The instrument was made of wood and metal, producing a pleasant tone when played.
The historical clarsach or Irish harp appears in the Coat of arms of Ireland, and on the flag of the President of Ireland as well as Irish Euro coins. The Coat of arms of Ireland is Blazoned as azure a harp or stringed argent - a gold Harp with silver strings on a St The Presidential Standard is the Flag of the President of Ireland.
As the Gaelic social order collapsed from the 17th century, harpers were no longer retained by patrons; instead their numbers declined and they became itinerant singer-songwriters touring a cirguit of lesser patrons. The famous Irish harper Carolan was such an itinerant singer-songwriter, accompanying his songs on a wire-strung harp.
By the 18th century the historical Scottish clarsach was extinct in Scotland, and the Irish harp died out in Ireland in the early 19th century. The last bearers of the tradition, Denis Hempson and others, played their music for Edward Bunting at Belfast in 1792, allowing it to be written down. Edward Bunting (1773 &ndash 1843 was an Irish musician and folk music collector The Belfast Harp Festival in 1792 was a three day event organised by Edward Bunting, age 19 at the request of James McDonnell and his committee called the Belfast Harpers Society Bunting published the music arranged for piano and his notebooks disappeared into the archives.
In the early 19th century, even as the old Gaelic harp tradition was dying out, a completely new harp tradition was invented in Ireland.  This Irish harp had gut strings and semitone mechanisms like an orchestral pedal harp, and was invented by Dublin pedal harp maker John Egan and marketed to aristocratic ladies. It was small and curved like the historical clarsach or Irish harp, but its strings and soundbox were modern.
In the 1890s a similar new harp was also developed in Scotland for the cultural Gaelic revival. 
These new instruments were popular and formed the basis of the 20th century revival in Ireland, Scotland and across the world. In Scotland they are called clarsach though in Ireland they are usually called Irish harp not cláirseach. Elsewhere they are called Celtic harp or folk harp or small harp or lever harp. Some have gut strings like the 19th century originals but many have nylon or carbon-fiber instead.
The modern clarsach or Irish harp has thousands of players, both in Scotland and Ireland, as well as North America and elsewhere. Notable events include the Edinburgh International Harp Festival.
Since the 1970s there has been a deliberate revival of the older wire-strung instrument, based on Early Music principles and using replica instruments and period playing techniques. Early music is commonly defined as European classical music from the Middle Ages, the Renaissance and the Baroque. Largely the work of one person, Ann Heymann, this movement is characterised by the use of accurate replicas of the museum instruments, fitted with brass, silver and gold wire strings, and using repertory and techniques taken from Edward Bunting's manuscripts and other historical sources. Edward Bunting (1773 &ndash 1843 was an Irish musician and folk music collector The main annual event is Scoil na gCláirseach held in Kilkenny every August. Scoil na gCláirseach is an annual summer school dedicated to teaching the Cláirseach, the historical Harp of Gaelic Ireland and Scotland Important CDs featuring historical music played authentically on replica medieval harps are Ann Heymann's Cruit go nÓr and Simon Chadwick's Clàrsach na Bànrighe. However the early clarsach remains much less popular than its modern rival.