Violin Concerto No.6 in E-flat major, KV 268/365b/Anh.C. 14.04

This violin concerto was first published by Johann André in 1799. A contemporary writer had stated the work to have been composed in 1784 and that it had been played to Eck by Mozart, although Mozart's widow Constanze stated that if authentic, the work must have been composed earlier. Ludwig von Köchel dated the work to 1776 in his catalogue, labelling it K. 268. A common hypothesis made in the later half of the 19th century was that the piece was based on authentic Mozart material but constructed by a less skilled composer. Cecil B. Oldman believed that the work had stylistic similarities to Mozart's sinfonia concertante for violin and viola, K. 364, and that Eck was the completer of the work, writing in a footnote to p.1469 of The Letters of Mozart and his Family Volume III: