Mozart was admitted as an apprentice to the Viennese Masonic lodge called "Zur Wohltätigkeit" ("Beneficence") on 14 December 1784. He was promoted to journeyman Mason on 7 January 1785, and became a master Mason "shortly thereafter". Mozart also attended the meetings of another lodge, called "Zur wahren Eintracht" ("True Concord"). According to Otto Erich Deutsch, this lodge was "the largest and most aristocratic in Vienna. ... Mozart, as the best of the musical 'Brothers,' was welcome in all the lodges." It was headed by the naturalist Ignaz von Born.
Freemasonry played an important role in the remainder of Mozart's life: he attended many meetings, a number of his friends were Masons, and on various occasions he composed Masonic music. At least as far as surviving Masonic documents can tell us, Mozart was well regarded by his fellow Masons. Many of his friends were Masons.
During his visit to Vienna in 1785, Mozart's father Leopold also became a Mason.