The Gaelic harp traditions of Scotland and Ireland were extremely conservative. Before they died out completely in the 19th century, they had stayed remarkably similar for almost 1000 years. Although obviously there were changes in the tradition1, there were many very particular elemnts that were retained over that time. This is a noticable contrast with European music generally which mostly consists of progressive traditions, constantly developing and cross-fertilising one another.
The origins of the triangular harp are lost in the mists of time, but from earliest times harps in Ireland and Scotland have been characterised by certain technical features. Most notable are metal strings, with two unison strings in the lower mid range2, played with the left hand in the treble and the right in the bass, with long fingernails3. The form of the harp did change in the 17th century, apparently in response to foreign developments, but the 'classic' Gaelic design uses only three large blocks of wood to make the soundbox (com), the harmonic curve (cor), and the forepillar (lamhcrann). Parallels can be drawn with much more ancient instrument building traditions attested by archaeology such as the Germanic lyres or even further afield the Scythian harps.
The tuning and modal system of the Gaelic harp is similarly conservative and although direct evidence is lacking older than the 17th or 18th century we may suppose it too has extremely ancient roots4. The connection between the developing medieval church modal system (which evolved into modern western music), the ancient Greek music theory, and the Gaelic music theory is very interesting but little has been done on it.
Another way in which the Gaelic harp traditions put down ancient roots is through acompanying vocal music. In this respect it bears close comparison with the work of Parry and Lord with South-East European epics5. This really does seem to have been a very ancient, pan-European tradition, or set of traditions, to perform large-scale poetry as song (whether you consider the performance style as singing, chanting or recitation is more of an aesthetic judgement), with string instrument accompaniment.