Mozart's musical ability started to become apparent when he was a toddler. He was the son of Leopold Mozart, one of Europe's leading musical pedagogues, whose influential textbook Versuch einer gründlichen Violinschule was published in 1756, the same year as Mozart's birth.
Leopold soon realized that he could earn a substantial income by showcasing his son as a Wunderkind in the courts of Europe. Mozart gained fame as a prodigy capable of playing blindfolded or with his hands behind his back, and for his ability to improvise wonderfully and at length on difficult passages he had never seen before. His older sister, Maria Anna, nicknamed “Nannerl”, was a talented pianist and often accompanied her brother on Leopold's tours. Mozart wrote a number of piano pieces, in particular duets and duos, to play with her. On one occasion when Mozart became ill, Leopold expressed more concern over the loss of income than over his son's well-being. Constant travel and cold weather may have contributed to his subsequent illness later in life.