April 12

Crusaders and Venetians under the old, nearly blind doge Enrico Dandolo broke through the sea walls and looted the city for three days. The four bronze horses of San Marco in Venice are part of the loot.

The crusaders broke in along the Golden Horn and plundered the city for three days. Niketas Choniates, who fled with his family, wrote that Saracens would have been kinder; the bronze horses of San Marco in Venice came from this loot.

From Candlemas to Easter 1349, Robert of Avesbury wrote, more than 200 bodies a day were buried in the new ground by Smithfield. At the other new cemetery, East Smithfield by the Tower, the dead lay in trenches; their teeth gave Bos and colleagues the Yersinia pestis genome in 2011.

Before the Inquisition he claimed the Dialogue had shown the Copernican arguments to be weak. The judges had in their file an unsigned note of 1616 saying he had been ordered not to discuss the doctrine “in any way whatever”.

At 4:30 in the morning Confederate batteries opened on the federal fort in Charleston harbour. After 34 hours Major Robert Anderson surrendered, and no one had been killed. A private died on the 14th when a gun blew up during the salute to the flag.

From the first shot at Fort Sumter to Lee’s surrender at Appomattox. The traditional count of the dead, about 620,000, goes back to William Fox and Thomas Livermore’s tallies. J. David Hacker’s 2011 census-based estimate is about 750,000, roughly as many as in all the nation’s other wars combined.

Five months between Lincoln’s election and the first shot. President Buchanan held secession illegal but found no power to stop it; Congress’s compromise plans, the Crittenden proposals above all, foundered on slavery in the territories.

Nathan Bedford Forrest’s cavalry stormed a Mississippi River fort held by about 600 men, half of them Black. Many were killed after they had surrendered, and far fewer Black soldiers than white were taken alive. Union casualties were 574 (NPS). “Remember Fort Pillow” became a battle cry.

Measuring with the electrometer Pierre and his brother Jacques had built, she found that the rays depended only on the amount of uranium, not its chemistry: a property of the atom itself. But pitchblende ore was more active than its uranium could explain, so it had to hold something unknown. Not a…

Germany surrendered in May 1945. Truman authorized the atomic bombings of Hiroshima and Nagasaki in August, and Japan surrendered formally on 2 September 1945.

He died of a cerebral haemorrhage at his retreat in Georgia, three weeks before Germany surrendered. Harry Truman, vice president for 82 days, was sworn in that evening and learned of the atomic bomb project only afterwards.

He died of a cerebral haemorrhage at his Georgia retreat while sitting for a portrait. Harry Truman, vice president for 82 days, was sworn in at 7:09 that evening in the White House Cabinet Room.

From Base Camp at about 5,450 metres Hillary, George Band and George Lowe forced a route through the Icefall; Sherpas then ferried tonnes of stores over its crevasses on ladders and ropes. When Hillary fell into a crevasse, Tenzing held him on the rope. Advance Base went up in the Cwm on 1 May.

Thomas Francis Jr. ran the largest medical experiment the United States had seen: about 1.8 million children, the “Polio Pioneers”, took part, and more than 600,000 were injected with vaccine or a placebo. The first shot went to six-year-old Randy Kerr at Franklin Sherman Elementary School in…

Francis announced the result at the University of Michigan, ten years to the day after Franklin Roosevelt’s death. That evening Edward R. Murrow asked Jonas Salk who owned the patent: “Well, the people, I would say. There is no patent. Could you patent the sun?”

Poyekhali! — “Let’s go!” One orbit in 108 minutes aboard Vostok 1. He ejected over the Volga and came down by parachute in a field near Engels, where a farmer’s wife and her granddaughter were the first to meet him. For the record books, Moscow said he had landed inside his capsule.

A meditation course at an ashram above the Ganges, with Donovan, Mike Love and Mia Farrow. Starr left after ten days, McCartney after five weeks, Lennon and Harrison in a hurry on 12 April after rumours about the Maharishi. With no drugs and no studio, they wrote most of their next album.

Marine helicopters lifted the American embassy staff and a few hundred Cambodians out of the besieged capital in a morning. Several of Lon Nol’s ministers, among them Sirik Matak, refused to leave.

President Carter had demanded Soviet troops leave Afghanistan by 20 February or the United States would stay away. They stayed, and so did the American team. In all 65 invited nations did not go to Moscow, for the boycott or for their own reasons.

OV-102, the first orbiter to fly and the heaviest. 28 missions, among them the first Spacelab, the Chandra X-ray telescope and the fourth Hubble servicing. Too heavy to be useful for the International Space Station, it never docked with it or with Mir.

John Young and Robert Crippen rode the first shuttle up at 7:00:03 in the morning, twenty years to the day after Gagarin. It was the first time the United States had put astronauts aboard a rocket that had never flown before, even unmanned.