Music Man - the Devil's interval.

What do "West Side Story" and "The Simpsons" have in common?  Listen to the first three notes of "Maria" and the first three notes of The Simpsons intro theme. They're the same, right?  The first two notes form what is known as a tritone - that is, they are three tones apart.  So what?  Well, back in the Middle Ages, when the Church (Catholic back then of course) pretty well ruled the world and decided what was what, this interval was deemed to be associated with Satan, and was banned. It was described as Diabolus in Musica (the Devil in music).  Of course, as any psychologist knows, to forbid something is an open invitation to those who like to challenge authority, and many composers took pleasure in concealing a tritone inside another chord (D⁷ contains the tritone C-F# for example).  But why the diabolical association?  Well listen to the intro to "Jonathan Creek".  This is a piece called "Danse Macabre" by Saint-Saëns and starts with a naked tritone played by a violin. And doesn't that sound a bit scary and spooky?  So there you are.