An unsuccessful attempt on the life of the king was made on 15 November 1620.
It occurred on Sunday at 9 in the morning when the monarch was to attend mass in St. John's Archcathedral in Warsaw.

Sigismund was to arrive by crossing a corridor or passage that linked the Royal Castle with the temple.
When the royal procession reached the end, hidden in a nearby portal was petty nobleman Michał Piekarski armed with a war hammer.
The assassin previously killed a Hungarian mercenary who was standing guard and the royal cook.
When the monarch reached the final steps, Piekarski leaped out and threw himself on the king, stabbing him twice, firstly in the back and then in the cheek, and striking him in the arm.
However, he was not able to deliver a fatal blow due to the intervention of royal guardsmen as well as Court Marshal Łukasz Opaliński who shielded the king.
Concurrently, Prince Władysław wounded the assassin on the head with a sabre.
Other accounts state that no guards were present; the cortege had a casual character and the assassin was most likely overpowered by the attendees.

Parishioners gathered around the pale and lifeless king, who collapsed to the ground after the incident.
The guards or other attendants were able to revive him and after a medical examination the wounds were found to be non-life-threatening.
Chaos erupted when false rumours spread that the king had been murdered as his clothes were stained in blood.
Initially, it was thought that the city was invaded by the Tatars.

The circumstances of this attack and the assassin were known exceptionally well after the attempt, as pamphlets soon appeared on the Market Square reporting three different viewpoints on the subject, published in a total of five editions.
The assassin was indeed Michał Piekarski, widely regarded as a mentally unstable melancholic, unrestrained in deeds, who as a child had suffered a head injury.
Piekarski's most probable cause for the assassination was fame and recognition; the successful assassination of Henry IV in Paris (1610) by François Ravaillac served as motivation for his actions.
For the appropriate moment Piekarski waited patiently 10 years.
At trial he did not deny the crime he committed and heavily insulted the jury, the Court Marshal, and the monarch.
He was executed in a similar manner as Ravaillac on 27 November 1620 in Warsaw, in a torture area called Piekiełko (Devil's Den or Devil's Place).
He was publicly humiliated, tortured and his body torn apart by horses.
An unsuccessful attempt on the life of the king was made on 15 November 1620. It occurred on Sunday at 9 in the morning when the monarch was to attend mass in St. John's Archcathedral in Warsaw.
Sigismund was to arrive by crossing a corridor or passage that linked the Royal Castle with the temple. When the royal procession reached the end, hidden in a nearby portal was petty nobleman Michał Piekarski armed with a war hammer. The assassin previously killed a Hungarian mercenary who was standing guard and the royal cook. When the monarch reached the final steps, Piekarski leaped out and threw himself on the king, stabbing him twice, firstly in the back and then in the cheek, and striking him in the arm. However, he was not able to deliver a fatal blow due to the intervention of royal guardsmen as well as Court Marshal Łukasz Opaliński who shielded the king. Concurrently, Prince Władysław wounded the assassin on the head with a sabre. Other accounts state that no guards were present; the cortege had a casual character and the assassin was most likely overpowered by the attendees.
Parishioners gathered around the pale and lifeless king, who collapsed to the ground after the incident. The guards or other attendants were able to revive him and after a medical examination the wounds were found to be non-life-threatening. Chaos erupted when false rumours spread that the king had been murdered as his clothes were stained in blood. Initially, it was thought that the city was invaded by the Tatars.
The circumstances of this attack and the assassin were known exceptionally well after the attempt, as pamphlets soon appeared on the Market Square reporting three different viewpoints on the subject, published in a total of five editions. The assassin was indeed Michał Piekarski, widely regarded as a mentally unstable melancholic, unrestrained in deeds, who as a child had suffered a head injury. Piekarski's most probable cause for the assassination was fame and recognition; the successful assassination of Henry IV in Paris (1610) by François Ravaillac served as motivation for his actions. For the appropriate moment Piekarski waited patiently 10 years. At trial he did not deny the crime he committed and heavily insulted the jury, the Court Marshal, and the monarch. He was executed in a similar manner as Ravaillac on 27 November 1620 in Warsaw, in a torture area called Piekiełko (Devil's Den or Devil's Place). He was publicly humiliated, tortured and his body torn apart by horses.
Sigismund III Vasa