In this book Bacciagaluppi shows how music practice was an occasion for cross-confessional contacts in 17th- and 18th-century Switzerland, implying religious toleration. The difference between public and private performing contexts, each with a distinct repertoire, appears to be of paramount importance. Confessional barriers were overcome in an individual, private perspective. Converted musicians provide striking examples. Also, book trade was often cross-confessional. Music by Catholic (but also Lutheran) composers was diffused in Reformed territories mainly in the private music societies of Swiss German towns (collegia musica). The political and pietist influences in the Zurich and Winterthur music societies encouraged forms of communication that are among the acknowledged common roots of European Enlightenment.