Previously posted at: https://www.history.com/this-day-in-history/thousands-die-in-massive-flood
On November 17, 1421, a storm in the North Sea batters the European coastline. Over the next several days, approximately 10,000 people in what is now the Netherlands died in the resulting floods.
The lowlands of the Netherlands near the North Sea were densely populated at the time, despite their known vulnerability to flooding. Small villages and a couple of cities had sprung up in what was known as the Grote Waard region. The residents built dikes throughout the area to keep the water at bay, but fatal floods still struck in 1287, 1338, 1374, 1394 and 1396. After each, residents fixed the dikes and moved right back in after the floods.
Even the St. Elisabeth’s flood of November 1404 (named after the November 19 feast day for St. Elisabeth of Hungary), in which hundreds died, could not dissuade the residents from living in the region. Seventeen years later, at the same time of year, another strong storm struck the North Sea. The resulting storm surge caused waves to burst hundreds of dikes all over Grote Waard. The city of Dort was devastated and 20 whole villages were wiped off the map. The flooding was so extensive this time that the dikes were not fully rebuilt until 1500. This meant that much of Zeeland and Holland–the area that now makes up the Netherlands–was flooded for decades following the storm. The town of Dordrecht was permanently separated from the mainland in the flood.