Piano_Concerto_No._10_(Mozart)
It is not known when Mozart completed his Concerto for Two Pianos and Orchestra in E-flat major, K. 365/316a, but research by Alan Tyson shows that cadenzas for the first and third movements are written in his and his father's handwriting on a type of paper used between August 1775 and January 1777[citation needed]. However, most sources, including Alan Tyson's book Mozart: Studies of the Autograph Scores[1] or more recently Lindeman's The Concerto: A Research and Information Guide (2006)[2] indicate that it was composed in 1779. It is presumed that Mozart wrote it to play with his sister Maria Anna ("Nannerl"). Years later he performed it in a private concert with pupil Josepha Barbara Auernhammer.