Who, on July 29 1014, following the Battle of Kleidon reportedly took approximately 15,000 prisoners. To crush the morale of his enemies, he ordered a mass blinding of the captured soldiers. The prisoners were divided into groups of 100. In each group, 99 men were completely blinded, while the 100th man was left with one eye. These one-eyed men were then forced to lead their 99 blind comrades back to their ruler.
Link: Wikipedia on Basil II