Background
Hässler was born in Erfurt. His father died in 1769 and from then on he also managed the family fur business, though he still managed concert tours of Germany in the early 1770s, then in other places in Europe in the 1780s and 1790s.
Hässler was born in Erfurt. His father died in 1769 and from then on he also managed the family fur business, though he still managed concert tours of Germany in the early 1770s, then in other places in Europe in the 1780s and 1790s.
He first studied under his uncle Johann Christian Kittel, who was an organist at Erfurt.
His first post was as organist of the local Barfilsserkirche in around 1762. On 15 April 1789 he entered an organ competition with Wolfgang Amadeus Mozart in Dresden during Mozart"s Berlin journey. On these tours he also came into contact with Johann Nikolaus Forkel, Johann Adam Hiller, Franz Benda, and Carl Philipp Emanuel Bach.
He remained there until his death.