Complex sentence: Confessing in open court to "carnal copulation" with Margaret Wheeler, he submitted himself for correction and was sentenced to open penance "in a white sheet (according to custom)" before the on three Sundays.
Split into simpler sentences: Confessing in open court to "carnal copulation" with Margaret Wheeler, he submitted himself for correction. He was sentenced to open penance "in a white sheet (according to custom)" before the on three Sundays.