Duchy of Prussia

State · 1526–1618 CE · at its largest around 1526 CE

The secular duchy created in 1525 when Albert of Hohenzollern, the last Grand Master of the Teutonic Order in Prussia, adopted Lutheranism and became a vassal of the Polish crown.

On its lands while it lasted

• Königsberg (1255–1945 CE): Capital of Duchy of Prussia (1526–1618), Brandenburg-Prussia (1619–1701).
• Nicolaus Copernicus (1473 CE – 1543 CE): Polish astronomer and canon of Frombork in Royal Prussia who proposed a Sun-centred model of the universe in De revolutionibus orbium coelestium, published in 1543, the year of his death.
• Copernican heliocentrism (1543 CE): Nicolaus Copernicus, a canon at Frombork, published De revolutionibus in 1543, placing the Sun rather than the Earth at the centre of the universe. It began the Scientific Revolution.

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