Why `override` is at the end in C++11?

I'm trying to see the reason why, in C++11, they had to add the override keyword at the end of the method instead of the beginning like virtual. I don't see the interest of being able to write both virtual and override in the declaration of a method.

Is there a technical reason why the committee didn't choose to simply be able to write override instead of virtual when it was needed?

Thanks!