The friendship between Mozart and Joseph Haydn is well known and started when Wolfgang moved to Vienna in 1781. But before he met Joseph, Mozart had already been a colleague to his younger brother, Michael Haydn. Michael had been in the service of the Archbishop of Salzburg starting in 1763, and then met Mozart who was still a child, albeit one a professional musician would notice. They later became colleague when Mozart joined the service of the Archbishop.

Much later, 1783, Michael Haydn was unable to complete a commission for six duets* for violin and viola due to a serious illness. To protect his friend from the wrath of Archbishop Colloredo, Mozart stepped in and ghostwrote the final two pieces.

*The Archbishop was also a Prince, and was himself a capable violinist. He had ordered these duets for his home entertainment.

These works, K. 423 in G major and K. 424 in B-flat major, are significantly more complex than the four Haydn had already finished. While the Archbishop reportedly couldn’t tell the difference, Mozart utilized sophisticated counterpoint and gave the lower part a much more prominent, virtuosic role than was typical for the genre at the time. Next weekend, Limor and Alicja will play the first one, K.423 in G Major.

The video below are excerpts from Limor and Alicja’s performance of that same duet in 2023 in San Pedro: