Who invented the saxophone?
Adolphe Sax.

When was the saxophone invented?
The saxophone was invented in 1840. However, he patented it in 1946.

Where was the saxophone invented?

Why was the saxophone invented?
The saxophone is designed to bridge the gap between woodwind and brass instruments.  It gives a stronger sound than the other woodwind instruments, but is mellower than brass instruments.

Is the saxophone a woodwind or a brass instrument?
Woodwind.  Although the saxophone is normally made of brass, the fact that it uses a single reed classifies it as as woodwind.

Is the saxophone considered a classical instrument?
Yes and no :) The saxophone is most commonly associated with Rock, PoP and Jazz.  It is typically not a standard part of a traditional symphony orchestra.  However, it is has been used my many classical composers including: Ravel’s Boléro, Benjamin Britten's Sinfonia da Requiem, Rachmaninov's Symphonic Dances and Bizet's L’Arlésienne suites.

The potential for the saxophone is unlimited
— Steve Lacy