[24] By 1588 the Spanish, under Alexander Farnese, Duke of Parma, had reconquered the southern Low Countries leaving only Ostend as a major rebel enclave along the coast and stood poised for a death blow against the nascent Dutch Republic in the north.

[25] Spain's concurrent enterprises against England and France at this time, however, allowed the Republic to begin a highly successful counter-offensive under Maurice of Orange which lasted from 1590–1600, known as the Ten Glory Years.

[31] In 1600 the Dutch and English Army under the command of Maurice of Nassau and Francis Vere respectively used Ostend as a base to invade Flanders, in an attempt to conquer the city of Dunkirk after their victory in the Battle of Nieuwpoort.

[14] At the northwest angle, near the mouth of the fordable old harbour, the walls consisted of a strong ravelin in the counter scarp called the Porcepic, and a bastion in its rear known by the name of the Helmund.

[39] The tercios consisted of recruited soldiers of all domains of the Spanish Habsburg empire; Spaniards, Portuguese, Italians, Germans, Walloons, Swiss, Burgundians loyal to Spain, and dissident Catholic Irish, along with mercenaries from other countries.

[35] On 5 July 1601, the Archduke Albert opened the siege of Ostend with 12,000 men and 50 siege-guns in position; while the small garrison of under 2,000 was commanded by Governor Charles van der Noot.

[44] The Count of Bucquoy, commanding forces east of Ostend, had been unable to do the same due over Geule, and began the construction of a dike from the sea up to the city; artillery was placed with which to fire at the boats coming and going from the North.

[42] On 27 July English troops led by Edward Cecil made a sortie and gained a large segment of trenches from the Spanish whom they put to flight; pursuing them to the sand hills with support from the town's artillery.

[42][50] Maurice however knowing the futility in making a direct attack, chose to campaign in the surrounding areas in an attempt to block the Spanish supplies and divert the attention of the besiegers.

[57] It was not until the end of November that the Spaniards had been at work advancing their batteries, forming foundations in the haven by sinking huge baskets of wicker-work filled with sand, and building floating platforms, on which guns were mounted in the "Geule".

[56] Vere made sure it was heavily guarded and placed Sir John Ogle's company there but was awoken by the alarm and rushed to the ramparts to discover the Spanish were assaulting the breach.

[62] In early January two of the besieging batteries, consisting of eighteen cannon, sent balls of forty to forty-six pounds weight, which kept up a crushing fire on the Porcespic, Helmund and Sandhill.

[63] Along the curtain of the old town, and on the breach which had been made under the "Sandhill", stones and bricks from the ruins of the old church, hoops bound with squibs, fireworks, ropes of pitch, and hand-grenades were ready to be poured on the attackers.

[69][71] The Spanish no sooner climbed to the crest of the "Sandhill" and the "Schottenburgh" but were repelled three times with heavy losses after rallying to the charge, while the struggle on the breach continued during the space of an hour.

[71] Vere saw an opportunity he could not miss, and ordered the west sluice to be opened, through which the waters that had been stored in the town ditch and had been closed at high tide now rushed down the haven in a huge torrent while the Spanish were wading across.

[65] Among the dead and wounded was the discovery of a young Spanish girl in male attire, who had fallen in the assault and under her dress was a chain of gold set with precious stones, along with other jewels and silver.

[76] Colonel Zelandés Frederic van Dorp, the new governor, arrived with a fresh rotation of eight Dutch and Frisian companies and by June more reinforcements put the garrison at 5,000 men in total.

[83] James at the same time discouraged the levy of English soldiers to help defend Ostend and declared a ceasefire at sea, in an effort to start peace talks with Spain.

[7] However, as a way to implement honor, the clause of the treaty would only take place once the siege of Ostend ended, with English and Scottish troops still both active in the field fighting with Maurice and in the garrison itself.

[92] After two years of campaigning, Archduke Albert's progress in the siege were scarce: attempts to attack the Old Haven in the west had not had the desired result, and the dike held by Bucquoy in the east had failed stop the boats from entering the city harbour.

[80] Ambrosio Spinola hoped to avoid the bloody and futile full-scale assaults of his predecessor and instead had his troops provided with a system of field fortification works that slowly advanced towards the northwestern part of Ostend.

[95] The inventions were not helping the Spanish however as Targone's mobile drawbridge mounted on four ten-foot wheels was damaged and immobilized by a single cannon shot; it was then destroyed by more fire from the besieged after which it was abandoned.

[92] Between February and March 1604 the city was badly damaged by severe storms and the Spanish continued to dig trenches ever closer and began constructing a mine under Porcepisc and the West Bulwark.

[97] Gieselles was killed soon after observing the captured position, and was succeeded by Colonel John van Loon, who died just four days later by the impact of a cannonball, his provisional substitute Jacques de Bievry was wounded and evacuated to Zealand.

[97] Meer was told there was a lack of earth so he ordered dead bodies from both sides to be used to shore up the ramparts of this final refuge; heads and bones were used like fascines but they could not offer adequate resistance to cannon fire.

[92] On 22 August two days after the surrender of Sluis, a combination of high tide and another storm swept away a significant proportion of the New Troy shrinking the defenders position further; the Northern defences were abandoned leaving only the Helmund and Sandhill lightly guarded.

[1] Maurice's capture of Sluis, however, had made it less essential for the Republic to hold on to Ostend; he and the States-General had assessed the situation with William Lodewijk pointing out that any such relief would be difficult.

[108][110] Three years, two months and two weeks of siege under almost constant fire of artillery as well as defence efforts to rebuild the walls at the expense of the buildings had left Ostend but a wasteland of rubble.

[108] After the eventual capture, Ambrosio Spinola was appointed field marshal general and supreme commander of the army in Flanders while Juan de Ribas, was made the new Governor of Ostend.

[126] According to American historian John Lothrop Motley and others, the siege of Ostend became progressively known as a 'great academy' in which the science and the art of war taught by the most skilful practitioners to all of Europe.