During this time, young Mozart had the opportunity to work in several different musical genres composing symphonies, string quartets, sonatas and serenades and a few operas.
Mozart and his father returned from their last stay in Italy in March 1773. His father’s benefactor, Archbishop von Schrattenbach had died and was succeeded by Hieronymus von Colleredo. Upon their return, the new archbishop appointed young Mozart as assistant concertmaster with a small salary. During this time, young Mozart had the opportunity to work in several different musical genres composing symphonies, string quartets, sonatas and serenades and a few operas. He developed a passion for violin concertos producing what came to be the only five he wrote. In 1776, he turned his efforts toward piano concertos, culminating in the Piano Concerto Number 9 in E flat major in early 1777. Mozart had just turned 21.