March 1, 1810: David Fisher quotes Valerie Matthews letter from Dariusz Proskurnicki in Poland, "Chopin himself presented his date as the 1st of March, 1810, as presented in his letter dated 1/16/1833 to the Head of the Literary Society in Paris. The same date is given in the letters of his Scottish pupil Jane W. Stirling, saying that "his parents made an error of eight days when they went to the registry office some weeks after his birth."
Juan Revilla quotes Bernard Gavoty, “Frederic Chopin, Charles Scribner’s Sons, NY 1977 for March 1. “This date was given by Chopin himself as told him by his father and this is the date that was celebrated by his family. In a letter to the Societe Litteraire Polonaise of Paris, in a letter dated January 11, 1833, Chopin says he was born March 1, 1810.”