October 9

Elijah ben Solomon Zalman, the Vilna Gaon and foremost leader of Lithuanian rabbinic scholarship, died in Vilnius.

Pope Pius XII, who led the Catholic Church through the Second World War and its aftermath, died at Castel Gandolfo.

Astronomer Karl Schwarzschild, born 9 October 1873 in Frankfurt, produced the first exact solution to Einstein's field equations in 1916, describing the geometry now linked to black holes.

On 9 October 1876 Alexander Graham Bell and Thomas Watson held the first two-way telephone conversation over an outdoor line, spanning roughly two miles between Boston and Cambridge.