Krystian Zimerman performs Beethoven's Piano Concerto No. 5, in E-flat major, Op. 73: fist movement, with the Vienna Philharmonic Orchestra, Leonard Bernstein conducting.
This is popularly known as the Emperor Concerto, which was completed in 1809, and premiered at the Gewandhaus in Leipzig in November 1811. The honours of the solo were given to Friedrich Schneider, a young church organist. When the “Emperor” premiered in Vienna, in February 1812, the solo part was interpreted by Beethoven’s pupil and friend Carl Czerny.
As for the title, "Emperor," that was not Beethoven's doing, notes a site dedicated to Beethoven
The powerful themes and heroic note of the composition, lead to the name Emperor for this concerto. The name “Emperor” dates from Beethoven’s time but was not given by Beethoven himself. Since the composer had little regard for emperors, he would be unlikely to name one of his own works for a class of people he disliked. While evidence is not clear, it seems that the name was given by a close friend of Beethoven, German composer Johann Baptist Cramer.In fact, Johann Baptist Cramer was considered an English musician of German extraction, whose parents moved to London when he was a young child. It was Cramer's publishing company, Cramer & Keyes (later J.B. Cramer & Co., Ltd.) in London, which was the English publisher of this concerto and which gave it the title of "Emperor."