Which composer wrote the Fifth Symphony that starts da-da-da-dum?

Beethoven, in 1808, and the opening is four notes that get taken apart and reassembled for the next thirty minutes - the rhythm turns up in every movement, sometimes buried in an accompaniment, sometimes as the main subject. It is an extraordinary demonstration of how little material a large structure needs.

He was going deaf while writing it, and had been since his twenties. By the premiere he could still hear something; within a decade he was conversing in writing, and when he conducted the Ninth Symphony's premiere in 1824 he had to be turned round to see the audience applauding because he could not hear it. He wrote the greatest of his music in silence, working from an inner sense of pitch and from the vibration of the instrument through the floor.

The four-note figure had a second life in the Second World War. Three short and one long is V in Morse code, and the BBC used it as the interval signal for broadcasts to occupied Europe - so a German composer's symphony became the sound of resistance to Germany. Beethoven himself is supposed to have said the motif was fate knocking at the door, though the source for that is his notoriously unreliable secretary.