Many, however, claim that the "Celtic" appellation is merely a marketing tag; the well known Galician bagpipe player Susana Seivane, said "I think [the 'Celtic' moniker is] a label, in order to sell more.
Some Galicians and Asturians have complained that the "Celtic boom" was the final death blow to once highly distinctive musical traditions.
The Suebi people conquered the northwest but the poor documentation from the period has left their cultural impact on the region unclear.
In the 6th century, a final small Celtic influx arrived from Britain; the Britons were granted their own diocese, Britonia, in northern Galicia.
This is assumed to have had a significant effect on the folk culture of the area, as the pilgrims brought with them musical instruments and styles from as far afield as Scandinavia and Hungary.
The Cantigas de Santa Maria, a collection of manuscripts written in old Galician, also show illustrations of people playing bagpipes.
The Galician folk revival drew on early 20th century performers like Perfecto Feijoo, a bagpipe and hurdy-gurdy player.
During the regime of Francisco Franco, honest displays of folk life were appropriated for politicised spectacles of patriotism, causing a sharp decline in the popularity of the traditional styles in favour of modern music.
Its mixture of tradition and modernity led BBC to choose the music of this album as the soundtrack of the TV program that broadcast the Galician image to Europe in the 1993 Xacobeo Celebration (Santiago de Compostela's Holy Year).
His 1996 A irmandade das estrelas sold more than 100,000 copies and saw major media buzz, partially due to the collaboration with well-known foreign musicians like La Vieja Trova Santiaguera, The Chieftains and Ry Cooder.
The first hit song that mixes Galician traditional music with electronics dates back to 1978, when the group Son Lalín launched their version of Muiñeira de Chantada, created by the producer Gustavo Ramudo.
Folk wind instruments of the area include the Cantabrian pitu montañés, a kind of conical-bored shawm with seven holes in the front and one in the back, which is played in a similar manner to the bagpipe chanter.
While it was traditionally made in E-flat, the instrument has been revitalized by Antón Corral, who makes them in D. A transverse flute with six holes is called a requinta; it is similar to the fife.
Despite the similarity in name, this instrument belongs to a different family than the Cantabrian pitu montañés, namely that of the fipple flutes, which also includes the tin whistle and the recorder.
Plucked stringed instruments are common throughout Spain and Portugal, but they were proscribed in Galician or Asturian commercial folk music until recent years.
Modern harpists have been encouraged by the use of the Celtic harp in Scotland, Ireland and Brittany, and include Quico Comesaña and Rodrigo Romaní.
Outside of Galicia and Asturias, bagpipes are also traditionally played in other parts of Spain, including Aragon, Catalonia, León, Majorca, Zamora and in Portugal in Minho, Trás-os-Montes and Estremadura.
The folk revival may have peaked in the late 1990s, with the release of acclaimed albums by Galician Carlos Núñez (A Irmandade Das Estrelas) and Asturian Hevia (Tierra De Nadie).
Air is driven into the chanter (Galician: punteiro; Asturian: punteru) with the left arm controlling the pressure inside the bag.
The bass drone (ronco or roncón) is situated on the player's left shoulder and is pitched two octaves below the key note of the chanter; it has a single reed.
Some bagpipes have up to two more drones, including the ronquillo or ronquilla, which sticks out from the bag and plays an octave above the ronco, or the smaller chillón.
Russian composer Nikolai Rimsky-Korsakov included three asturian movements (two Alboradas and one Fandango Asturiano) in his famous orchestral work Capriccio espagnol, Op.
Their origin is shrouded in mystery, with some scholars asserting Gregorian chants as a major source, while others fancily point to Greek or Phoenician rowing songs called alelohuías.
Alalás are arhythmic, and based on a single, short theme that repeats the melody, separated by instrumental bagpipes or a cappella interludes.
Other Asturian dances include saltón, diana, respingu, pericote, fandango, pasodoble, marcha procesional, rebudixu, corri-corri, baile de los pollos, giraldilla and xiringüelu.
Other popular dance songs in the area include the jota, pasacorredoiras (pasacalles, Asturian: pasucáis), and the imported fandango, mazurka, polka, rumba and pasodoble.