The Abbess of Vlaye by Stanley J. Weyman

It was after midnight, and the young moon had set when they came, a long procession of riders, to the ford in which des Ageaux had laved his horse's legs on the evening of his arrival. But the night was starlight, and behind them the bonfire, which the men had rekindled that its blaze might aid their preparations, was reflected in a faint glow above the trees. As they splashed through the shallows the frogs fell silent, scared by the invasion, but an owl that was mousing on the slope of the downs between them and the dim lifted horizon continued its melancholy hooting. The women shivered as the cool air embraced them, and one here and there, as her horse, deceived by the waving weeds, set a foot wrong, shrieked low.

But no one hesitated, for the Bat had put fear into them.