An interesting discussion in BYZANS-L began with this comment:
Pero Tafur had an interesting conversation in 1437 with John VIII. He had complained to John about a theft, the thief was taken, his eyes put out and his hands cut off. Pero asked why they didn’t just execute him. John said that no man had the right to condemn another man’s soul. Pero comments that one saw a lot of mutilated people in Constantinople.
Pero Tafur was a Spanish visitor to Constantinople at that time. His book, translated by Ross and Power, is here. It’s from chapter 17:
One day the Castilian captain who was there sent for me, because one of his men had been killed at sea by a Greek, with intent to steal his ship, and I went to him, and we took the criminal and the corpse to the Emperor that justice might be done. Although the Greeks did not wish it, yet out of his great regard for me, and because I said that our people might otherwise take vengeance upon those who were innocent, the Emperor sent at once for the executioner, and in front of the Palace he ordered the criminal’s hands to be cut off, and his eyes to be put out. I enquired why they did not put him to death, and they replied that the Emperor could not order his soul to be destroyed.
They told me also that when Charlemagne took Jerusalem, on the way by which his people had to return, many of them travelled through Greece and were killed by the Greeks, and that the others, when they heard of this, took the road through Tartary and Russia, where the inhabitants were Christians, and from there they passed into Hungary and Germany. It is said that the reason why the Russians of those parts are so beautiful, is that many Frenchmen settled there and married. The Emperor Charlemagne then came up against Constantinople, and made great war on the Emperor of Greece, but in the end they had to make peace, and the Emperor, as penance for the killing of those men, promised to fast during the whole of Lent, which they say is observed differently than with us (since the Greeks cannot reconcile it with their consciences to eat fish with blood, but only shell-fish, and, further, that no one, however great his crime, should be put to death, but that the punishment was to be loss of hands and eyes. In Greece, therefore, there are many maimed and blinded men.
This is the manner in which the Despot gave us justice, and we were content with what he did.
An interesting attitude; that maiming is more merciful than death. It is easy for us to be interested in the Byzantines; but they enjoyed an evil reputation in Europe, weak, unmilitary, crafty and cruel. Their vices destroyed them, and we should remember this. For their fate awaits every society that forgets simple virtues for the sake of expediency and abstract dogma.
On the other hand, there was probably many an emperor who would have said that becoming emperor might not be the best thing in the world, given the short life expectancy, but it was better than a poke in the eye with a sharp stick!