History of the Slag om Grolle (Battle of Groenlo)

During the Eighty Years’ War (1568-1648), the struggle of the rebellious states of the Netherlands against Spain was led successively by Willem van Oranje, and his sons Maurits and Frederik Hendrik. The Achterhoek, but also large parts of Brabant, Limburg and Overijssel, were the scene of the Eighty Years’ War in the second half of the 17th century. As a result, there was absolutely no Golden Age here. The predominantly Catholic population of these regions did not really want to be “liberated” by the Prince’s armies.

The siege of the town ‘Grol’ during the summer of 1627 is re-enacted bi-annually during the Slag om Grolle (Battle of Groenlo). On 20 July 20 1627, the State Army – led by Prince Frederik Hendrik – came for “the strong city of Grol”. An event that briefly, but unequivocally, brought the city to the center of national and European history.

When the Eighty Years’ War broke out in 1568, it initially remained fairly quiet in the Achterhoek. In 1578 the States of Gelderland joined the Orange. Groenlo is therefore Staats from that moment.
1568 - 1578
Because the city was left unoccupied by the State troops, the fortress was transferred to Spanish hands in 1580, without any notable struggle. An earthen wall is being laid over the vulnerable city walls.
1580
Prince Maurits came to the city on July 14th, 1595. However, the prince is forced to abort his siege on July 24th because it becomes clear that the general Mondragon is heading towards Grolle with a large Spanish army.
1595: eerste poging
But not for long: on September 1st, 1597, Maurits returns for the fortress. After a fierce battle, the Spanish occupation on September 26th is forced to surrender to the prince. This puts Grolle in state hands.
1597: Grolle in Staatse handen
On August 4th, 1606, a large Spanish army led by Spinola arrives at the city. Ten days later the State occupation must already capitulate. Grolle remains in Spanish hands until the siege of 1627.
1606: Spinola verovert Grolle
The Twelve-year-old truce is used by the Spaniards to modernize the fortress. The river “De Slinge”, which previously flowed through the city canal, is led around the city. In addition, the fortress is provided with a sixth bastion.
1609-1621 - Twaalfjarig bestand
After a mine explodes, heavy fighting takes place. When it becomes clear that the State troops are planning to let two more mines explode, the city commander, Matthys Dulken, gives up the fight and capitulation negotiations start.
1627 - Mijnen
The surrender treaty is signed on August 19th, 1627. Grolle belongs to the State and remains that for the remainder of the Eighty Years’ War.
1627 - Capitulatie
The prince remained in Groenlo for thirty days. The battered city will be put back in resilient condition as quickly as possible. Frederik Hendrik implements the Spanish plan from the Twelve-Year truce, to provide the fortress with six ravelins.
1627 - Na de capitulatie
Frederik Hendrik succeeded his brother Maurits in 1625. The State army, consisting of 20,000 men and 5,000 horsemen, is shipped to the east. On July 20th, 1627 the army arrived at the town of Grol.
1627 - Frederik Hendrik
The prince has a circumvallation line constructed, a 17 km line of defense that completely shuts the city off from the outside world. Day and night 8,000 burial diggers and soldiers work on the circumvallation line.
1627 - Circumvallatielinie
Starting from the soldier’s quarters, the State soldiers start digging zig-zag trenches to the city. The city is also under attack from that moment on by the cannons and mortars that the prince has taken on his campaign.
1627 - Loopgraven

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