WHAT DO THE PEOPLE IN CASTERBRIDGE KNOW ABOUT HENCHARD'S PAST?

They know he was a drunkard.

"But I know that 'a's a banded teetotaller, and that if any of his men be ever so little overtook by a drop he's down upon 'em as stern as the Lord upon the jovial Jews."

But they don't know what happened to his wife, and they believe him to be a widower.