The Scots are not at fault. Traditionalists in the Association of Galician Bagpipers blame their own compatriots for introducing "foreign forms alien to the Galician tradition". But reformers in the Royal Bagpipers Band from Orense, east of Vigo, say their innovations are the fruit of "rigorous historical research" and have nothing to do with Scotland.
The row has been rumbling for years, since Franco's death in 1975 permitted the flowering of Galicia's cultural identity, and particularly its purest expression, the bagpipe or gaita. In the latest skirmish, the Association accused the Royal Band of "deceiving" the Pope by giving him a Scottish bagpipe which it passed off as authentically Galician.
The director of the Royal Band, Xose Lois Foxo, said that the instrument handed to the Pope during a recent performance at Castelgandolfo was the real thing, crafted by traditional artisans in Orense. "The fundamental mission of our band is to promote the music of Galicia and dignify this traditional instrument," said Mr Foxo last week.
It was true, he conceded, that massed bands of bagpipers were more a Scottish than a Galician tradition: the gaiteiro historically plays alone or in groups of three or four and the full flowing knee-length trousers worn by his players bear a passing similarity to the kilt, said Mr Foxo, "but this costume simply revives pre-18th century Galician dress". Drums, too, are more generally associated with Scottish forms, he agreed. "But we are all part of a Celtic musical culture, and share common roots. Many traditionalists just can't accept the link."
Santiago Caneiro, president of the Association of Galician Bagpipers, retorts that massed pipe bands are a martial tradition brought from Scotland with no part in Galician popular culture. "I've got nothing against Scottish bagpipes, but I don't agree with the implantation of their military formulas into our tradition," he said.
Nor was there any evidence that the kilt-like trousers were authentically Galician. The design was based on a 13th century engraving, said Mr Caneiro, "but it could have come from any part of the Celtic world". Mr Foxo's band, in his eyes, was more interested in courting popularity and influence than preserving traditions.
The Royal Band, 2,000 of whose bagpipers accompanied Manuel Fraga when he was inaugurated as Galicia's Prime Minister in 1990, won the prize for Best Overseas Pipe Band in the Highland Games of 1991 and 1993. "The traditionalists are just jealous of our success," says Mr Foxo.
Bagpipes are hot at the moment, and not just in towns like Vigo where you can hear gaiteiros in dim portside taverns while knocking back orujo, a fearsome local moonshine that tastes of stables. Galicia's bagpipe king, Carlos Nunez, is wowing them at concerts all over Spain with music from his latest album, made with the Irish folk band The Chieftains and guitarist Ry Cooder.
His music drips with morrina, the mournful nostalgia endemic to this part of Spain, steeped in mystical legends. But Nunez takes a relaxed view of the origins of his favourite instrument. "It is curious the different forms of gaita that there are in many cultures. It's not just Scottish or Irish. In some sense the traditions all converge."