October 14

Twenty-one miles of grey water separate England from the continent, and for a thousand years that strip of Channel has been the most consequential moat on earth: too narrow to keep an army out, too wide to make crossing it anything but a gamble with weather, tide, and nerve. October 14 is, improbably, a day about that water and the men who learned to command it. Three of them. A conqueror who crossed it, a general who was born to cross it again, and a marshal who died having failed to defend the far shore.

The first crossing succeeded in a single afternoon. On October 14, 1066, the Norman Conquest of England began with the Battle of Hastings, and by dusk an Anglo-Saxon kingdom had a Norman owner. William had ferried horses and men across the same sea the Romans had crossed, betting everything on one field and one day. The bet held. The language, the law, the very shape of England bent to it.

Eight hundred and twenty-four years later, on October 14, 1890, the man who would mount the next great cross-Channel invasion was born. Dwight D. Eisenhower, the American general and eventual 34th president, spent the spring of 1944 assembling the largest amphibious force in history and pointing it at the Normandy coast, reversing William’s direction of travel, sending an army from England back across the water to wrest the continent loose. He carried in his pocket a note accepting blame should the landings fail. They did not.

Waiting on the other side was the third man. Erwin Rommel, the German field marshal charged with fortifying that coastline against exactly the invasion Eisenhower launched, had walked the beaches and seeded them with obstacles, convinced the war would be decided in the first hours on the sand. He was right about the stakes and wrong about the outcome. On October 14, 1944, implicated in the July plot against Hitler, Rommel was made to swallow poison in exchange for a quiet funeral and the safety of his family. The defender of the Channel coast died four months after it was breached.

The date keeps company with other firsts and edges. In 1888 Louis Le Prince filmed the first motion picture, the brief Roundhay Garden Scene, teaching the world to cross time as easily as water. In 1906 Hannah Arendt, who would spend her life writing about power and violence and the men who wield both, was born. And in 2012 Felix Baumgartner stepped off a balloon at the edge of space and fell back through the stratosphere, crossing a frontier no army ever had. Conquest is mostly a question of which barrier a man decides is passable. October 14 is the anniversary of several answers.