Exhibits, Shows and Displays

What word can be used to describe someone who stands up for their beliefs?

I can't quite put my finger to it. There's a word for it, isn't there? One that describes someone who stands up for their beliefs?

Public Comments

1. STAUNCH....
2. Integrity. peace
3. martyr?
4. Activist?
5. LATE BLOOMER ahaha! reliable
6. stubborn passionate
7. Campaigner Protester Activist Assertive Radical