Luar na Lubre is something of an institution in Galician music. They started off in 1986 and are still going strong.
I have a greatest hits CD that´s great accompaniment for the part of the trip where the dryish Province of Leon gives way to the lush green countryside of Galicia.
They´re currently on tour, unfortunately not to Madrid.
From Wikipedia in Spanish -
The music of Luar na Lubre relies heavily on the folklore of Galicia, but is also heavily influenced by the countries within the "Celtic" tradition as the area round the Atlantic has a particular way of making music, an aesthetic used and adapted by many Galician folk groups and, in many ways thanks to this, the music of Galicia has acquired a level of internationalization previously never thought possible. Still, there are certain "traditionalists" who criticize this movement.
Their style has evolved considerably over the years, gradually becoming more sophisticated. In 1996 the British musician Mike Oldfield issued the Voyager album including an adaptation of O Son do Ar, and invited the group on his world tour, which gave Luar Na Lubre international fame. In 2003, the song ¨Memoria da noite¨ was composed, referring to the sinking of the Prestige oil tanker off the Galician coast.
In 2009, Luar Na Lubre celebrated it´s 25th anniversary, recording their first live album (Ao Vivo) at the Teatro Colon in La Coruña and inviting musicians like Luz Casal, Pedro Guerra and Diana Navarro to join them.
In November 2010 their latest work came out: "Solstice", a project that marks a new beginning for the group, a different direction in their trajectory that points to medieval music, the richness of medieval Galician-Portuguese lyrics, influences from the pilgrimmage route the Camiño de Santiago, and the introduction of different cultures expressed through music. Solstice is a mixture of religion and paganism, the acoustic and electrical sounds of the past and present, from that which is intrinsically Galician, from a Galicia looking at the world as an equal now and into the future.