The Celtic harp is a triangular harp traditional to Brittany, Ireland, Scotland and Wales. It is known as a telenn in Breton, cláirseach in Irish, clàrsach in Scottish Gaelic and telyn in Welsh. In Ireland and Scotland, it was a wire-strung instrument requiring great skill and long practice to play, and was associated with the Gaelic ruling class. It appears on the coins and coat of arms of the Republic of Ireland.
A characteristic feature is the metal strings. Historical sources mention various types of wire, including brass and iron; some scholars also argue for the use of silver and gold. The wires were attached to a massive soundbox typically carved from a single log, commonly of willow, although other woods including alder and poplar have been identified in extant harps. This harp also had a reinforced curved pillar and a substantial neck, flanked with thick brass cheek bands. The strings, usually played with the fingernails, produced a brilliant ringing sound. This type of harp is also unique amongst single row triangular harps in that the first two strings tuned in the middle of the gamut were set to the same pitch.
The playing of the wire-strung harp is considered to be extremely difficult. Because of the long-lasting resonance, the performer had to dampen strings which had just been played while new strings were being plucked, and this while playing rapidly. Contrary to conventional modern practice, the left hand played the treble and the right the bass.