Renaissance of the Celtic Harp was recorded in 1972 and I discovered it a few years later through a Welsh speaking friend in Aberystwyth University. I ha it first on cassette tape then vinyl. An instrumental album, it is the work of the Breton Celtic harp master Alan Stivell. I suppose the idea of marrying traditional folk music with modern rock music, classical music and (in this case) world music was in the air at the time and this album works very well in that progressive idiom.
The Celtic harp itself was pretty obscure instrument to me until I heard this album (The Chieftains had one. Their album The Celtic Harp came out over 20 years later in 1993). The mixture of instruments (cello, harp, electric guitars, modern drums, traditional snares and table, etc) and "its evocation of a utopian atmosphere" made it a benchmark for Celtic music revival that was apparently going on in the seventies. Music critic Bruce Elder was full of hyperbole when he wrote of the album at the time "People who hear this record are never the same again." Certainly it is one of the most beautiful and haunting records ever made.
Part of its genius is that it draws on music from practically all the Celtic nations (so increasing sales potential and saying something political at the same time). The opening work, Ys, is inspired by the legend of the 5th century capital of the kingdom of Cornwall. Other pieces are from Brittany, Wales, Scotland Ireland and even the Isle of Man.