Colonel Schelte van Aysma died in 1637 during the Eighty Years' War as Dutch Protestants battled for independence from their Spanish rulers, a Dutch military spokesman said.

But the soldier's remains had lain almost entirely forgotten for centuries beneath a heavy gravestone in the local floor of Schetten church.

"Today, the remains of Colonel Van Aysma will be reburied with full military honours in a newly restored grave," Captain Joost Ploegmakers told AFP.

It is not clear exactly how Van Aysma died, but he was killed during the 1637 Siege of Breda, when the southern fortress city then held by the Spanish was surrounded by troops loyal to the Netherlands. The Dutch finally recaptured the city after a year-long siege.

The investigation of how the remains of Van Aysma -- considered a hero of the Dutch struggle for independence from Spain -- were discovered reads like a cold-case detective story.

After being lost for centuries, officials from the Dutch National Military Museum discovered Van Aysma's helmet in 2015 still hanging in Schetten's local church.

Amateur historian Andre Buwalda spotted a similar depiction of Van Aysma's helmet on a gravestone, which was promptly opened.

Despite a partial cave-in, there were enough human remains to take for testing. "DNA tests confirmed it was indeed that of Colonel Van Aysma," army spokesman Ploegmakers said.

The ancient soldier's remains will now be placed in a new coffin and carried by soldiers of the local Johan Willem Friso Regiment, the oldest and most senior regiment in the Dutch current order of battle.

"His remains will then be resealed in the newly-restored tomb" in the church, Ploegmakers said.

The Dutch military often rebury newly-discovered remains of soldiers killed during World War II -- particularly British and American plane crews shot down during bombing raids.

"To be able to rebury a soldier from the Eighty Years' War and a senior officer like a colonel at that, is really unique," Ploegmakers said.