So, what should he play?
The audio of conductor Erich Leinsdorf halting a Boston Symphony Orchestra concert to announce the assassination of President John F. Kennedy has been unearthed.
The recording, from November 22nd 1963, begins with Leinsdorf addressing the audience and telling them the news that JFK has been assassinated. The concert was being broadcast on US radio station WGBH at the same time.
He then continues by announcing that the BSO will play, in tribute, the slow movement from Beethoven's Symphony No.3, the Eroica.
The clip was unearthed by the American Archive of Public Broadcasting, who have begun a series of similarly culturally significant broadcasts in the hope that they will be preserved.
According to James Inverne's report in Time magazine , the orchestra and conductor were informed of the assassination before the concert began, and were given the music for the funeral march as they walked on to the stage.
The orchestra had begun the concert with works by Handel and Sydeman, and were scheduled to play some Rimsky-Korsakov when the announcement was made.