Since, therefore, we have the authority of Vattel, of Frederick the Great, and of Lord Wolseley that spies may or even must be employed in war, and that, be the trickery or bribery never so mean that procures their services, no discredit reflects itself upon those generals who use them--it is impossible not to notice it as one of the chief anomalies in existing military usages that, although a general has an unlimited right to avail himself of the services of a spy or a traitor, the penalty for acting in either of the latter capacities is death. The capital penalty is not of itself any test of the moral character of the action to which it is affixed, for the service of a fire-ship, which demanded the most desperate bravery, used to be undertaken in the face of capital punishment. Moreover, some of the most famous names in military history have not hesitated to act as spies. Sertorius was honoured by Marius with the usual rewards of signal valour for having learnt the language of the Gauls and gone as a spy amongst them disguised in their dress. The French general Custine entered Mayence in the disguise of a butcher. Catinat spied out the strength of Luxembourg in the costume of a coal-heaver. Montluc entered Perpignan as a cook, and only resolved never again to act as a spy because the narrowness of his escape convinced him, not that it was a service of too much dishonour, but a service of too much danger. The custom of killing spies is an old Roman one,[195] and, indeed, seems to have prevailed all the world over. Nevertheless there have been exceptions even to that. Scipio Africanus had some Carthaginian spies who were brought before him led through the camp, and then dismissed under escort, and with the polite inquiry whether they had examined everything to their satisfaction.[196] The consul Lævinus is said to have dealt in the same way with some spies that were taken, and so did Xerxes by some Greek detectives. At the famous siege of Antwerp in 1584-5, when a Brabant spy was brought before the Prince of Parma, the latter gave orders that he should be shown all the works connected with the wonderful bridge that he was then constructing across the Scheldt, and then sent him back to the besieged city with these words: ‘Go and tell those who sent you what you have seen. Tell them that I firmly intend either to bury myself beneath the ruin of this bridge or by means of it to pass into your city.’