whom he visited in London in 1764 and 1765. When he was eight years old, Mozart wrote his first symphony, most of which was probably transcribed by his father. The family trips were often challenging, and travel conditions were primitive. They had to wait for invitations and reimbursement from the nobility, and they endured long, near-fatal illnesses far from home: first Leopold (London, summer 1764), then both children (The Hague, autumn 1765). The family again went to Vienna in late 1767 and remained there until December 1768. After one year in Salzburg, Leopold and Wolfgang set off for Italy, leaving Anna Maria and Nannerl at home. This tour lasted from December 1769 to March 1771. As with earlier journeys, Leopold wanted to display his son's abilities as a performer and a rapidly maturing composer. Wolfgang met Josef Mysliveček and Giovanni Battista Martini in Bologna and was accepted as a member of the famous Accademia Filarmonica. There exists a myth, according to which, while in Rome, he heard Gregorio Allegri's Miserere twice in performance in the Sistine Chapel. Allegedly, he subsequently wrote it out from memory, thus producing the "first unauthorized copy of this closely guarded property of the Vatican". However, both origin and plausibility of this account are disputed. In Milan, Mozart wrote the opera Mitridate, re di Ponto (1770), which was performed with success. This led to further opera commissions. He returned with his father twice to Milan (August–December 1771; October 1772March 1773) for the composition and premieres of Ascanio in Alba (1771) and Lucio Silla (1772). Leopold hoped these visits would result in a professional appointment for his son, and indeed ruling Archduke Ferdinand contemplated hiring Mozart, but owing to his mother Empress Maria Theresa's reluctance to employ "useless people", the matter was dropped and Leopold's hopes were never realized. Toward the end of the journey, Mozart wrote the solo motet Exsultate, jubilate, K.165. 1773–77: Employment at the Salzburg court After finally returning with his father from Italy on 13 March 1773, Mozart was employed as a court musician by the ruler of Salzburg, Prince-Archbishop Hieronymus Colloredo. The composer had many friends and admirers in Salzburg and had the opportunity to work in many genres, including symphonies, sonatas, string quartets, masses, serenades, and a few minor operas. Between April and December 1775, Mozart developed an enthusiasm for violin concertos, producing a series of five (the only ones he