A bit late here Carol--You didn't mention what part of Europe you wanted circus music from, or what time period--or what kind of circus--as a small child, I lived in Italy, and remember the circus music as having sounded much like the music from Fellini movies(an intentional effect in the Fellini movies, I always thought) which is to say, they were striking. lilting melodies, often in a minor key, with a driving dance pulse, often a tarentella or a tango--the melodies could be traditional tunes, but often were popular songs from an older time(operatic marches count as popular songs, as well, at least in Italy)--

About ten or twelve years ago, I saw a small Scandinavian children's circus that had a band which sounded like I remembered the Italian carnival music--it had a trombone, trumpet, saxophone, drum, accordian and violin, and they were wonderful--