Johann Peter Fritz was a piano maker based in Vienna.
[2] It is known, that Giuseppe Verdi was very fond of Johann Fritz's pianos and used the Viennese 6-pedal Fritz piano from the time of Rigoletto in 1851 to Aida in 1871.
This exact piano can be seen in the composer's Villa Verdi in Province of Piacenza in Italy.
After Johann Fritz's death, his son Joseph (born in Vienna, 1808), continued the firm, apparently under the original name.
[3] Recordings made with original Fritz pianos