Swedish troops under Charles IX captured the fortress of Kexholm from Russia during the Ingrian War, expanding Swedish control over the eastern Baltic.

Galileo's continued telescopic observations of Jupiter's moons, recorded in early October 1610, provided mounting evidence against an Earth-centered cosmos.

Tokugawa Ieyasu ordered construction of Nagoya Castle to begin, a massive fortress meant to secure Japan's strategic Tokaido road and project Tokugawa dominance.