The Twelve Years' Truce ended in 1621. StadtholderMaurice of Orange had in the meantime played a part in instigating the Thirty Years' War in Germany. The Habsburgs tried to punish the rebellious Dutch Republic by cutting it off from its hinterland by a land blockade. 's-Hertogenbosch was the main fortress in this perimeter and enormous sums of money were poured into the improvement of its defences. As the ground surrounding the city was a marsh, the city was generally deemed to be impregnable, as the water-saturated soil seemed to make an application of current siege methods impossible; trench-digging and undermining were apparently out of the question. Maurice had failed twice in taking the city.
The blockade caused an economic crisis for the Republic and it reacted by trying to harm the enemy in its colonies. In 1628 one of the many schemes undertaken met with spectacular success when Admiral Piet Hein of the Dutch West India Company captured the Spanish treasure fleet. The vastly improved financial situation of the Republic allowed for a major counter-stroke and StadtholderFrederick Henry decided to break the Habsburg morale by conquering their main stronghold in the Netherlands. This came very unexpectedly; most had... Read More