To murder enemies who had surrendered was as contrary to Greek or Roman as it ever was to Christian warfare. The general Greek and Roman practice was to allow quarter to an enemy who surrendered, and to redeem or exchange their prisoners.[22] There was indeed, by the laws of war, a right to slay or enslave them, and though both rights were sometimes exercised with great barbarity, the extent to which the former right was exercised has been very much exaggerated. Otherwise, why should Diodorus Siculus, in the century preceding our era, have spoken of mercy to prisoners as the common law (τὰ κοινὰ νόμιμα), and of the violation of such law as an act of exceptional barbarity?[23] It may be fairly doubted whether the French prisoners in the English hulks during the war with Napoleon suffered less than the Athenian prisoners in the mines of Syracuse; and as to quarter, what of the French volunteers or Franc-tireurs who in 1870 fell into the hands of the Germans, or of the French peasants, who, though levied and armed by the local authorities under the proclamation of Napoleon, were, if taken, put to death by the Allies in 1814? Some other illustrations tend further to show that there is no real progress in war, and that many of the fancied mitigations of it are merely accidental and ephemeral features. The French and English in olden time used to spare one another’s fishing boats and their crews. ‘Fishermen,’ said Froissart, ‘though there may be war between France and England, never injure one another; they remain friends, and assist each other in case of need, and buy and sell their fish whenever one has a larger quantity than the other, for if they were to fight we should have no fresh fish.’[24] Yet in the Crimean war, the English fleets in the Baltic seized or burnt the fishing boats of the Finns, and destroyed the cargoes of fish on which, having been salted in the summer months, they were dependent for their subsistence during the winter.[25] Polybius informs us that the Œtolians were regarded as the common outlaws of Greece, because they did not scruple to make war without declaring it. Invasions of that sort were regarded as robberies, not as lawful wars. Yet declarations of war may now be dispensed with, the first precedent for doing so having been set by Gustavus Adolphus. Gustavus Adolphus, in 1627, issued some humane Articles of War, which forbade, among other things, injuries to old men, women, and children. Yet within a few years the Swedish soldiery, like other troops of their time, made the gratuitous torture and mutilation of combatants or non-combatants a common episode of their military proceedings.[26]