30,000 gathered to hear him speak

Without a microphone.

He traveled all around the country to preach.

On foot.

Bernadine of Siena, the most powerful preacher of the century, literally wore himself out in the service of God: dropping to the ground and dying on this very day in 1444 (the vigil of the Ascension that year). He was canonized six years later.

(adapted from an earlier post)