Written for Joseph Leutgeb, the Salzburg horn player who had settled in Vienna as a cheesemonger and remained Mozart's friend and the butt of his jokes; four concertos and a fragment were composed for him. Long dated to 1783, K. 447 is now placed around 1787 on the evidence of the paper and the handwriting of the autograph. It is the only one of the four accompanied by clarinets and bassoons rather than oboes and horns, which gives it a darker, chamber-like sound, and its slow movement is a Romanze of a kind Mozart rarely wrote for a wind soloist.