Friedrich Buschmann had invented the accordion’s basic…

Friedrich Buschmann had invented the accordion’s basic form in Berlin in 1822; Cyrill Demian in Vienna first patents an instrument called accordion in 1829.

Demian's instrument (which bears little resemblance to modern instruments) has only a left hand keyboard, with the right hand simply operating the bellows.

One key feature for which Demian had sought the patent is the sounding of an entire chord by depressing one key.

In what is called a bisonoric action, his instrument also can sound two different chords with the same key: one for each bellows direction (press, draw).

The patent, for an instrument called the accordion, is applied for by Demian on a May 6 and officially approved on May 23.