Musical Key Question

Why do classical radio stations always state the key of the music as well as the name?

Isn’t it the case that, for example, Beethoven’s #5 is always in C minor? I would think that the name would nail down the key and if not, for some reason, then state the key.

It’s not just the classical radio stations - album packaging and performance announcements for classical pieces often include the key. And yes, they are generally performed in one particular key, but it’s still a tradition to refer to them that way. Equal temperament only became commonly accepted for symphonic works from about the 18th century on … before then, the key of the piece would have been more significant.

It was always my understanding that the key was part of the title and it’s the number that’s an artificial application of later scholars. In other words, Beethoven didn’t write “Symphony No. 1” which happens to be in C major, he wrote “Symphony in C major,” which happens to be symphony number 1.

Maybe, but Beethoven has at least two symphonies that share a key: numbers 6 and 8 are both in F major. (Or, they’re arranged that way now anyway.)