One that comes quickly to mind:-from the Bundshuh Rebellion March 17, 1525
Roughly translated as "Thoughts are Free" (Wolfgang Hell, please help me out if you've a more elegant translation!), it addresses the power of thought and expression in a rather rousing way.
I remember it from a Limeliters album in the late 50s/early 60s, when it played a part in kindling my commitment to progressive social causes. (It's in the database, too.)