There are, or rather were, many ancient indigenous music traditions all over Europe. However the Gaelic harp tradition is unusual, if not unique, amongst them, for a combination of reasons:
Nowadays, most music in Europe is descended from Italian art music of the 17th century. Because this general continuing style is so universal in today's music, it is often un-noticed, or considered ‘normal’. When it is noticed and described, it is sometimes described as ‘classical’ or ‘common practice’.
Present day traditional, popular, world and electronic musics all share in and draw from this heritage.
However, all over Europe, there was music before the spread of the Italianate worldview, which did not follow the rules, styles or forms of ‘common practice’. Most of these ancient oral traditions became marginalised and died out a long time ago.
It’s my opinion that we can usefully compare these different traditions, to get a better overview of the variety and diversity of indigenous European music from the past.
The European context: the Gaelic harp traditions have Progressive connections with mainstream European musical life, as well as conservative connections as fossilised primal repositories. As with other medieval arts, the early Gaelic harp has accumulated much detailed and esoteric lore.