Among the earliest references to music from Catalonia date to the Middle Ages, when Barcelona and the surrounding area were relatively prosperous, allowing both music and arts to be cultivated actively. Catalonia and adjacent areas were the home for several troubadours, the itinerant composer-musicians whose influence and aesthetics was decisive on the formation of late medieval secular music, and who traveled into Italy and Northern France after the destruction of Occitann culture by the Albigensian Crusade in the early 13th century. The so-called Llibre Vermell de Montserrat ("Red Book of Montserrat") stands as an important source for 14th-century music.