At the age of four he could learn a piece of music in half an hour, and by the age of six he was performing publicly and beginning to write his own symphonies. Around this time the family began to tour throughout Europe, performing at the courts of Munich, Paris and London. During his tours Mozart met many famous composers, including Johann Sebastian Bach, who would end up having a strong influence on him. By the time Mozart was thirteen, he and his sister had toured extensively throughout Europe. However, while his sister had to abandon touring and prepare to find a husband, Wolfgang was appointed assistant concertmaster to the archbishop at the age of seventeen. It was during this period that Mozart expanded his repertoire with several new pieces, as well as developing a fondness for violin and piano concertos. He ended up composing five violin concertos and the piano concerto number 9 in E flat major