Laudator Temporis Acti

Helen Langdon, Caravaggio: A Life (New York: Farrar, Straus and Giroux, 1998), pp. 340-341:

The late sixteenth century, when the Ottoman Empire threatened, and the religious militancy of Spain was at its height, was a glorious period in the Knights' history. In 1565, in the Great Siege of Malta, they had, against terrible odds, and suffering appalling losses, fought off a massive Turkish onslaught made by the most powerful Turkish sovereign, Suleiman the Magnificent. The Siege was marked by individual feats of heroism and macabre acts of cruelty. The Turks floated the bodies of decapitated knights on wooden crucifixes in the Grand Harbour, and Jean de La Valette Parisot, the Grand Master, who became an almost legendary hero, responded by firing Turkish heads from the guns of Fort St Angelo.

René-Aubert Vertot (1655-1736), The History of the Knights Hospitallers of St. John of Jerusalem; Styled afterwards, The Knights of Rhodes, And at present, the Knights of Malta. Translated from the French, Vol. IV (Edinburgh: Alexander Donaldson, 1770), pp. 347-348:

Mustapha, of a cruel and bloody nature, by way of revenge, and at the same time to terrify the knights that were in the town, and the other fortresses of the island, ordered such as were found found lying among the dead, and had still any marks of life left, to be ripped open, and their hearts to be plucked out. To this unexampled piece of barbarity, the Basha, in order to insult the instrument of our salvation, which the knights wore as the badge of the Order, had gashes made over their body in form of a cross, when putting their subrevests upon them, they tyed them to planks, and threw them into the sea, hoping, as indeed fell out, that the tide would carry them to the foot of the town and the castle of St. Angelo.

This dismal and shocking spectacle drew tears from the Grand Master. His first sensations were those of grief, but his next were those of anger and indignation; in consequence of which, and by way of reprisals, he, in order to teach the Basha to make war with less barbarity, ordered all the Turkish prisoners to be immediately executed; and ramming their heads into his cannon, had them shot, all covered with blood as they were, instead of ball, into the camp of the infidels.