To appreciate the allegory involved in _The Enraged Swan_ it is necessary to summarize the events that followed the conclusion of the truce in 1621. Spain would have been glad to substitute for the truce a permanent peace, but held out for terms that were unacceptable to the Hollanders; and war in a desultory fashion was renewed. By this time the Thirty Years’ War had commenced, and the religious and political struggle, that hitherto had centered in Holland, was being continued in a distant and larger field. Maurice died in 1625 and was succeeded in the office of Stadtholder by Frederick Henry, an able soldier and wise and patriotic statesman, who set himself to consolidate the internal resources of the republic. The latter showed its recognition of his services by the fatal expedients of making the office of Stadtholder hereditary in the house of Orange and of agreeing to the marriage of Frederick’s son William with the eldest daughter of Charles I. The effects of this were, on the one hand, to create within the republic an Orange party that in time intrigued for absolutism of government, and, on the other, to embroil Holland in the struggle between the Stuarts and the Parliament of England, and later, upon the restoration of the monarchy in the person of Charles II, to involve the republic both in diplomacy and in war with that utterly unprincipled person. Meanwhile peace was finally concluded with Spain in 1648, by the Treaty of Westphalia, or, as the compact is also styled, the Peace of Münster, which was proclaimed on June 5, 1648, the day on which Egmont and Horn had been executed by Alva eighty years before. By this time Frederick had been succeeded in the Stadtholdership by his son William, who, with the assistance of the Orange party, was intriguing for absolute rule. Fortunately for the republic, his death occurred two years later, a few days before the birth of his son, who eventually became Stadtholder and subsequently William III of England. Meanwhile, during the prince’s minority, the government was in the hands of Johan de Witt, whose book “The Interest of Holland” is an able summary of the political and commercial conditions of the republic at the time. His patriotism had been whetted to a personal edge by the fact that he had been imprisoned illegally and arbitrarily by the late Stadtholder, and his opposition to the pretensions of the Orange party was in consequence unceasing throughout his official term, which lasted from 1650 to 1672. It is this that is commemorated in _The Enraged Swan_.