The year 1629 brought three formidable armies at once to the frontiers of the republic, and caused a general dismay all through the United Provinces; but the immense treasures taken from the Spaniards enabled them to make preparations suitable to the danger; and Frederick Henry, supported by his cousin William of Nassau, his natural brother Justin, and other brave and experienced officers, defeated every effort of the enemy.  He took many towns in rapid succession; and finally forced the Spaniards to abandon all notion of invading the territories of the republic.  Deprived of the powerful talents of Spinola, who was called to command the Spanish troops in Italy, the armies of the archduchess, under the count of Berg, were not able to cope with the genius of the Prince of Orange.  The consequence was the renewal of negotiations for a second truce.  But these were received on the part of the republic with a burst of opposition.  All parties seemed decided on that point; and every interest, however opposed on minor questions, combined to give a positive negative on this.

The gratitude of the country for the services of Frederick Henry induced the provinces of which he was stadtholder to grant the reversion in this title to his son, a child of three years old; and this dignity had every chance of becoming as absolute, as it was now pronounced almost hereditary, by the means of an army of one hundred and twenty thousand men devoted to their chief.  However, few military occurrences took place, the sea being still chosen as the element best suited to the present enterprises of the republic.  In the widely-distant settlements of Brazil and Batavia, the Dutch were equally successful; and the East and West India companies acquired eminent power and increasing solidity.

The year 1631 was signalized by an expedition into Flanders, consisting of eighteen thousand men, intended against Dunkirk, but hastily abandoned, in spite of every probability of success, by the commissioners of the states-general, who accompanied the army, and thwarted all the ardor and vigor of the Prince of Orange.  But another great naval victory in the narrow seas of Zealand recompensed the disappointments of this inglorious affair.

The splendid victories of Augustus Adolphus against the imperial arms in Germany changed the whole face of European affairs.  Protestantism began once more to raise its head; and the important conquests by Frederick Henry of almost all the strong places on the Meuse, including Maestricht, the strongest of all, gave the United Provinces their ample share in the glories of the war.  The death of the archduchess Isabella, which took place at Brussels in the year 1633, added considerably to the difficulties of Spain in the Belgian provinces.  The defection of the count of Berg, the chief general of their armies, who was actuated by resentment on the appointment of the marquis of St. Croix over his head, threw everything into confusion, in exposing a widespread confederacy