Johannes Chrysostomus Wolfgangus Theophilus Mozart was his name at christening. It varied greatly though and there is an interesting article about that here (which addresses the name "Amadeus"): http://en.wikipedia.org/wiki/Mozart%27s_name Also, in Marcia Davenport's biography Mozart, it is said that his father added Sigismund as a confirmation name though it was never used. This was probably (though not certain) done as a courtesy to the Mozart family patron Archbishop Sigismund.

This question could well have been posted by one of my students, as I ask it in class! Names as used were in many ways a matter of style in those days. For example, prior to the French revolution, when it was stylish to seem Italian, Ludwig van Beethoven used to sign his first name as "Luigi." Subsequent to the French revolution, when it was hip to seem French, he used "Louis." In the Renaissance, when Italianate musical styles were popluar, Composers of all nationalities used Italian translations of their names, such as the Flemish composer Orlando di Lasso (Roland Delattre) and the English Orlando Gibbons (Roland Gibbons). Also, composers who worked for the church would often Latinize their names. One example is the German late-renaissance composer Michael Praetorius. "Praetorius" is Latin for guard or protector, which, translated into German, gives us his real name, Michael Schultz. Mozart's name was similarly subject to change. His birth record reads Johannes Chrisostomus Wolfgangus Theophilus Mozart. The word theophilus is greek for "God's love," which in German (Mozart's native language), translates to Gottlieb, the name actually used in place of Theophilus throughout Mozart's childhood. In his maturity, he often used Latin translation of God's Love, Amadeus, but he often signed letters with the French Amadé. By the way, actual first names were not commonly used in normal parlance at the time. Johann Sebastian Bach, for instance, went by Sebastian. As was customary at confiration at the time, Mozart took the name of the person who presented him for confirmation. This was his father's partoon, Prince Archbishop Sigismund of Salzburg. So, an understanding of all of Mozart's names could be seen in the following chart. Johannes Chrisostomus Wolfgangus Theophilus Mozart Sigismundus Chrisostom Wolfgang Gottlieb Amadeus Amadé