The Step on the Neck Legend

Modern historians pooh-pooh this story, beloved by the Venetians, as apocryphal, but it was widely believed by German humanists in the 16th century. In 1545, Martin Luther wrote a pamphlet entitled The Pope's Threat which offered the German point of view of the famous incident that took place in the narthex of St Mark's Basilica in 1177:

Upon returning from his crusade, which culminated in the capture of Jerusalem, Frederick Barbarossa opened a new just war, this time against the pope. He was determined to wreak vengeance on Alexander III who had betrayed him into a yearlong captivity at the court of the sultan in Armenia.

Alexander, who had already excommunicated Barbarossa for erecting an antipope Victor, smarted from the defeat of his anti-imperial Lombard league and was jealous of the emperor's piety, secretly had a portrait of Barbarossa painted and sent to the sultan with a plea to murder him. But the sultan, so moved by the Christian witness of the pious Barbarossa, released him upon his pledge to ransom his chaplain.