How did Nicola Porpora help Joseph Haydn develop as a composer?

After Joseph Haydn was dismissed from his choir school and left to support himself through odd musical jobs, he sought to improve his skills through self-instruction. A significant turning point in his development occurred when he met the Italian composer and singing teacher Nicola Porpora.1

Porpora played a vital role in Haydn’s professional growth by accepting him as an accompanist for voice lessons. During this time, Porpora provided direct mentorship by reviewing and correcting Haydn’s compositions. Additionally, while in Vienna, Porpora gave Haydn formal composition lessons, which helped the young musician refine his craft as he transitioned toward his later career as a master composer.12