After the Nazis seized power in Germany, Krupp supported the regime and was one of many German businesses that profited from slave labor during World War II.

Being a major weapons supplier to multiple sides throughout various conflicts, it was sometimes blamed for the wars themselves or the degree of carnage that ensued.

[3][4] Friedrich Krupp (1787–1826) launched the family's metal-based activities, building a pioneering steel foundry in Essen in 1811.

[6] An account cited that, on his deathbed, the elder Krupp confided to Alfred, who was then 14 years old, the secret of steel casting.

[6] This next generation Krupp (1812–87), known as "the Cannon King" or as "Alfred the Great",[8] invested heavily in new technology to become a significant manufacturer of steel rollers (used to make eating utensils) and railway tyres.

He also invested in fluidized hotbed technologies (notably the Bessemer process) and acquired many mines in Germany and France.

Initially, Krupp failed to gain profit from the Bessemer process due to the high phosphorus content of German iron ores.

[9] Unusual for the era, he provided social services for his workers, including subsidized housing and health and retirement benefits.

Low non-military demand and government subsidies meant that the company specialized more and more in weapons: by the late 1880s the manufacture of armaments represented around 50% of Krupp's total output.

In 1943, by a special order from Hitler, the company reverted to a sole-proprietorship, with Gustav and Bertha's eldest son Alfried Krupp von Bohlen und Halbach (1907–67) as proprietor.

In 1951, as the Cold War developed and no buyer came forward, the U.S. occupation authorities released him, and in 1953 he resumed control of the firm.

In 1968, the company became an Aktiengesellschaft and ownership was transferred to the Alfried Krupp von Bohlen und Halbach Foundation.

The unexpected victory of Prussia over France (19 July 1870 – 10 May 1871) demonstrated the superiority of breech-loaded steel cannon over muzzle-loaded brass.

Prussia fortified the major North German ports with batteries that could hit French ships from a distance of 4,000 yd (3.7 km; 2.3 mi), inhibiting invasion.

More crucial to the operations of the German military was Krupp's development of the famed 88 mm anti-aircraft cannon which found use as a notoriously effective anti-tank gun.

During World War II, it was designed to divert Allied airstrikes from the actual production site of the arms factory.

The shortage of volunteers led the Vichy government of France to deport workers to Germany, where they constituted 15% of the labor force by August 1944.

Low pay, long hours, frequent bombings, and crowded air raid shelters added to the unpleasantness of poor housing, inadequate heating, limited food, and poor medical care, all compounded by harsh Nazi discipline.

In an affidavit provided at the Nuremberg Trials following the war, Dr. Wilhelm Jaeger, the senior doctor for the Krupp slaves, wrote: Sanitary conditions were atrocious.

The Tatars and Kirghiz suffered most; they collapsed like flies [from] bad housing, the poor quality and insufficient quantity of food, overwork and insufficient rest...Countless fleas, bugs and other vermin tortured the inhabitants of these camps..."[12] The survivors finally returned home in the summer of 1945 after their liberation by the allied armies.

This was a heavy duty replacement for the original pressure sphere (made in Italy by Acciaierie Terni) and was manufactured in three finely machined sections: an equatorial ring and two hemispherical caps.

Krupp received original contracts in the United States and enjoyed a period of technological superiority while also contributing the majority of rail to the new continental railway system.