July 20 ephemeris

July 20 ephemeris

1944: Operation Valkyrie:Hitler escapes an assassination attempt fomented by Count Claus von Stauffenberg, and in which many German officers are involved.

1881: Sioux chief Sitting Bull surrenders to the US Army.

1031: The King of France Robert II The Pious dies in Melun at the age of 61.

911: By the Treaty of Saint-Clair-sur-Epte, King Charles the Simple proposed in 911 to Chief Rollo and his Vikings to settle in the region of Rouen, which would become the Normandy.

Video: Lecture 28: GPS errors and DGPS