The German invasion of the Netherlands began on May 10, 1940, eight months after the start of the Second World War. German bombers struck military airfields and barracks around The Hague, while paratroopers were used to capture tactical points and support the advance of ground troops.
Adolf Hitler justified the attack with a lie, claiming that England and France had been planning to attack Germany through the Netherlands and Belgium. The Netherlands surrendered on May 15, 1940, and signed a capitulation agreement.
Soon after, the Nazis occupied the whole country and introduced anti-Jewish laws designed to exclude Jewish people from society and restrict their livelihoods. The systematic deportations of Dutch Jews to death camps began in July 1942.
Some Dutch citizens could not bear to see what was happening to their country and its people, and they joined the resistance. One of them was a young neurologist and committed anti-fascist who decided he must act, and who even killed Nazis. His name was G. Kastein.
Kastein was born on June 25, 1910, in the town of Zutphen in the Netherlands. As a child he was bright and serious, and he studied hard. After finishing his basic education, he chose to dedicate his life to medicine.
He began his medical training at the University of Groningen and later studied in Germany and in Leiden in the Netherlands. In 1937, he graduated as a doctor.
During his stay in Germany, Kastein met a German woman named Elizabeth. They married and had two children together. His career as a neurologist took him first to Leiden and then to The Hague.
Even before the Second World War began, Kastein's beliefs drew him into public life. At first he joined a socialist party, and later he became a member of the Communist Party of the Netherlands.
He wrote articles for the party's journal and gave lectures about the dangers of fascism, and he also campaigned against racism. He was not only active in writing but also fought actively against Nazism.
He helped to smuggle communists out of Nazi Germany and went to Spain when the Spanish Civil War erupted in 1936. As a neurologist, he volunteered with a medical team to help the Republican side in the battle against fascist units later led by Spanish dictator Francisco Franco.
In Spain, he worked among the wounded, and on his return he shared what he had witnessed. The stories of brutality and courage only deepened his hatred of fascist ideology. In 1938, he published a book condemning racism and warning about the consequences of political indifference.
The Second World War began on September 1, 1939, when Nazi Germany invaded Poland. In May of the following year, Germany attacked the neutral Netherlands.
Within hours, vital positions were under attack and confusion spread among both soldiers and civilians. Rotterdam, an important port city, became a central target.
As German troops pushed closer, the Dutch government tried to negotiate, but the Germans demanded total surrender. On May 14, 1940, in an effort to break the Dutch resistance, German bombers unleashed a devastating air raid on Rotterdam's city center, setting huge parts of the city ablaze and killing hundreds of people.
Thick smoke rose for miles, and the destruction shocked the country. Under the threat that other cities like Utrecht and Amsterdam would suffer the same fate, the Dutch commander-in-chief, General Henri Winkelman, decided to capitulate.
The following day, Queen Wilhelmina and the Dutch government fled to London, a few days earlier, to continue the fight against Nazi Germany from exile. Only the province of Zeeland held out a little longer, until it too was overrun.
With the surrender complete, the Netherlands fell under German military occupation. Daily life changed almost overnight. German soldiers patrolled the streets, strict curfews were imposed, and all public gatherings were controlled until the end of the war.
The occupation authorities targeted Jewish citizens, political opponents, and anyone suspected of resisting Nazi rule. Many Dutch people felt a deep sense of humiliation and disbelief that their neutral country had been overpowered so quickly.
Some hoped the war would soon be over, while others already began to think about how they might resist the new rulers. In this atmosphere of shock and fear, as the Netherlands fell under German military rule almost overnight, Kastein felt more certain than ever that he could not stay passive.
The sudden collapse of Dutch defenses and the brutal bombing of Rotterdam convinced him that the Nazis would stop at nothing to break the country's spirit. For a man already committed to fighting fascism, the surrender on May 15, 1940, was not just a military defeat, it was a moral challenge.
While many around him tried to adapt or hoped that life would eventually return to normal, he saw clearly that occupation would only allow the Nazis to grow stronger. Just days after the capitulation, on May 17, 1940, he attended a secret meeting of Communist Party members in The Hague to discuss how they could reorganize underground activities.
He understood that with the queen and government in exile, there was no legitimate Dutch authority left to protect freedom inside the country. From that moment on, Kastein believed it was up to ordinary citizens to resist in whatever ways they could.
The fall of the Netherlands transformed him from a respected neurologist into a determined resistance leader willing to risk everything to oppose the forces that had turned his homeland into an occupied territory. Kastein became involved in resistance activities, and the first attempt to arrest him by the Nazi security authorities took place on September 2, 1941.
However, Kastein was warned in time, went into hiding, and continued his resistance activities. In 1942, he worked with a resistance group known as CS6, named after the address at 6 Goristraat in Amsterdam, where several resistance members lived and often met.
CS6 specialized in gathering military intelligence and planning assassinations of key Dutch collaborators with the Nazi regime. Kastein also worked closely with non-communist resistance groups.
He had intended to have photographs of German defenses along the Dutch coast delivered to the Dutch government in London through such resistance groups. However, the courier of the resistance group later turned out to be a German double agent, Anton van der Waals, who slipped the film roll not to the government in exile in London but directly into German hands.
By the end of 1942, Nazi leaders were preparing to create a Dutch Nazi administration to support Germany's Eastern Front campaigns. The Germans believed that by installing loyal Dutch officials and terrorizing the local population, they could suppress any rebellion in the occupied Netherlands.
The CS6 group decided that visible collaboration with Nazi Germany had to be punished, to warn others and to damage German plans. On February 5, 1943, they ambushed General Hendrik Seyffardt, a retired Dutch officer who had agreed to serve the Germans.
Seyffardt was an interesting figure. Before the war, he had served as chief of staff of the Dutch army, and in 1934 he went into retirement. He came out of it during the occupation of his country by the Germans and served them as a willing collaborator and as a figurehead for the Volunteer Legion Netherlands, a unit of the Waffen SS, the military branch of the SS created by Dutch citizens on the Eastern Front.
After approval from the Dutch government in exile, on the evening of February 5, 1943, after answering a knock at his front door in The Hague, Seyffardt was shot twice by student Jan Verleun, who had accompanied Kastein on the mission. A day later, Seyffardt died in hospital.
A few days later, another attack prepared by Kastein and CS6 members targeted Hermanus Reyden, a member of the Dutch National Socialist Movement and a journalist turned collaborator with the Nazis. Reyden was seriously wounded and died of his wounds in August 1943. His wife, Wilhelmina, died during the attack.
These attacks outraged the Germans, and in retaliation they launched a campaign of reprisal killings and terror. Nazi death squads and Dutch collaborators carried out executions of prominent civilians, former soldiers, doctors, and priests accused of sympathizing with the resistance.
Instead of destroying morale, these brutal acts spread more bitterness and made the occupation even more hated. But the Germans were successful in one thing: they captured Kastein.
On February 19, 1943, Kastein was supposed to meet with a fellow communist resistance fighter in Delft near The Hague. They were to discuss a plan to simultaneously set fire to all employment offices in the Netherlands to complicate the deportation of Dutch men for forced labor in Nazi Germany.
However, German security services had caught the resistance fighter previously, and during the search they found a note of the meeting in his notebook. Precisely on time, Kastein entered the cafe and was immediately seized by the Germans and taken to a car parked outside with false license plates.
An agent from the SD, the intelligence agency of the Nazi party, was waiting in the car. Once inside, a struggle ensued, during which Kastein managed to pull a pistol from his jacket pocket and fire, seriously wounding the German agent. When the car drove away, a small pool of blood remained on the street.
During a search, the SD found a notebook containing a written record of a meeting with communist resistance fighter Lucas Boore. Later that day, Kastein agreed to cooperate in attending the meeting. The meeting was held at a coffee house in the park.
There, SD officer Johannes Hoffman got out and walked to the coffee shop, which was ten meters off the road. Kastein, whose hands were cuffed, managed to retrieve a pistol and shot another SD officer in the leg. He then jumped out and ran away, but he was quickly overtaken.
He was placed in the car, and as it drove away, four armed men burst out of the cafe. The car drove on, and when Kastein was ordered to get out, he managed to pull another pistol and shot himself in the chest, but the bullet from the weapon ricocheted.
After this struggle, Kastein was taken for interrogation. This was the moment when he made his final decision and decided to sacrifice his life before revealing any resistance secrets to the Nazis.
On February 21, 1943, while being interrogated by the German security service in an interrogation room, and while left alone, the 32-year-old Kastein jumped, still handcuffed and attached to the chair, from a third-story window. On landing, he fractured his skull and died a few hours later.
Although he died relatively young, he is still remembered as one of the greatest heroes of the Dutch resistance during the Second World War.