September 3, 1658 — Oliver Cromwell dies

Hated by the Irish for his invasion the previous decade, Oliver Cromwell’s manner of death must have given them some satisfaction. He died from a malarial fever contracted during the invasion (and complicated by what appears to have been kidney stones).

Cromwell had come far and acheived much in his 59 years, but little that he had built long-survived him. His son Richard, who succeeded him as Lord Protector, resigned from that role due to a lack of political support less than a year later, and King Charles II was invited back to England to reinstate the monarchy the year after that.

In 1661, on the anniversary of King Charles I’s execution, Cromwell’s corpse was exhumed, and a symbolic posthumous beheading was carried out. His severed head would be a collector’s item for some years thereafter, before being reburied in 1960.

WarwickCastle CromwellDeathmaskcrop.JPG
By Chris Nyborg – Wikimedia Commons, CC BY-SA 3.0, Link

As mentioned in:

Oliver Cromwell — Monty Python

September 3, 1941 — Zyklon B is first used at Auschwitz

One of the deadliest chemicals ever invented, Zyklon B is a derivative of Prussic acid. It was invented in 1922 by a small team of German chemists led by Nobel Prize winning chemist Fritz Haber, whose previous creations included mustard gas and other chemicals of warfare used in World War One.

In 1941, the gas was first deployed in three death camps: Auschwitz-Birkenau, and Majdanek, and Sachsenhausen. Its first large scale use was one September 3, when 600 Russian POWs, 250 Polish POWs and 10 criminals were killed at Auschwitz-Birkenau. Some of the victims survived more than 24 hours of exposure to the gas – when this was discovered, additional quantities of it were pumped into the killing chambers. By the time the war ended, an estimated 1.2 million people were killed with Zyklon B, most of whom (960,000) were Jews.

Birkenau a group of Jews walking towards the gas chambers and crematoria.jpg
By anonymous, possibly SS photographers E. Hoffmann & B. Walter – Auschwitz Album ([https://collections.ushmm.org/search/catalog/pa8538 record in USHMM collection), Public Domain, Link

As mentioned in:

Point of No Return — Immortal Technique