Were Mozart and Haydn Freemasons?

Yes, they were both Freemasons, but in different lodges. In fact, it was Mozart who encouraged Haydn to join. This fact should not be over-interpreted, however, as the condemnation of Freemasonry by the Holy See (1738) was not promulgated (made public law) right away in the Hapsburg empire of which the two famous composers were subjects. They both would have regarded themselves as Catholics, and they wrote some of the most lovely Mass settings and religious music in history. One has only to hear Haydn’s setting of the litany of Our Lady or Mozart’s Ave Verum to know that they were not plotting against the Faith.

The Church’s struggle with Freemasonry is a long-term effort, and it has never been completely successful, as so many men (they don’t allow women, even today!) choose the social advantages of Masonry, convincing themselves that they are not doing anything contrary to their faith, when in fact they are, as the Church has repeatedly taught down to the present Holy Father. Pope Francis asked Cardinal Raymond Burke, for example, to make sure that there were no Masonic inroads into the Order of Malta.