April 11

Batu forced the bridge over the Sajó with stone-throwers while Subutai crossed downstream, and the Hungarian camp was surrounded. A gap was left open and the fleeing army was cut down along the road. King Béla IV escaped and was chased to the Adriatic coast.

First heard at Good Friday vespers in the Thomaskirche, written for two choirs and two orchestras. The date was long given as 1729; research in the 1970s moved it two years earlier.

They reached Rome in Holy Week and went to the Sistine Chapel on the Wednesday and the Thursday to hear Allegri’s Miserere, which the papal singers were forbidden to copy on pain of excommunication. Leopold to his wife, 14 April: “But we have it already. Wolfgang has already written it down.” The…

About 150 Luddites attacked William Cartwright’s mill at night, to break his shearing frames. He had soldiers inside, and two attackers were shot and died. Charlotte Brontë set the raid in her novel Shirley.

Fred Gaisberg of the Gramophone Company recorded the 29-year-old tenor in a single afternoon at the Grand Hotel et de Milan, for a fee of £100. The records sold in London before Caruso had sung there and persuaded famous singers that the gramophone was worth their while.

Three trips before the winter laid about 3,000 kilograms of food and fuel at 80°, 81° and 82° south. Each depot was marked with a line of flags running east and west, so a party that missed it in fog would still cross the line.

Bertrand Russell’s appeal to scientists to warn the world about hydrogen-bomb war reached him in his last days, and he agreed to sign in a letter to Russell. Russell heard of his death on a flight to Paris and found the letter waiting: one of Einstein’s last acts.

The Fair Housing Act is signedFair Housing Act

Title VIII of the Civil Rights Act of 1968 banned discrimination in the sale, rental and financing of housing. Stalled in the House for weeks, it passed the day after King’s funeral, and Johnson signed it a week after his death.

LiftoffApollo 13

13:13 in Houston, from Launch Complex 39A. Three days before, the command module pilot, Ken Mattingly, had been grounded for exposure to German measles; his backup, Jack Swigert, flew in his place. Mattingly never caught it.

Violent “pogo” oscillations shut the centre engine of the Saturn V’s second stage down 2 minutes 12 seconds early (GET 0:05:30). The other four engines and the third stage burned longer to make up for it, and the flight went on.

A turn and a third around the Earth at about 185 kilometres, checking every system before committing to the Moon.

The third stage fired for almost six minutes and sent the spacecraft towards its landing site in the Fra Mauro highlands, the target Apollo 14 would inherit.

Translunar coastApollo 13

We’re bored to tears down here. — Joe Kerwin, Houston, nine hours before the explosion Two days in which the flight went as smoothly as any before it. Transcript: Apollo 13 Flight Journal

Swigert turned the command module Odyssey around and docked nose to nose with the lunar module Aquarius, then pulled it free of the spent third stage. Nobody expected the lander to become the crew’s home within three days.

The trio rapped and danced “Nan Arayo” on an MBC talent show, and the judges gave them the lowest score of the night. The song spent 17 weeks at No. 1 anyway, and their mix of rap, dance and pop became the template for K-pop.

A magnitude 8.6 earthquake struck off northern Sumatra, the largest strike-slip shock ever recorded. Warnings went out across the ocean within minutes and coasts from Aceh to India were evacuated. Because the fault moved sideways, the sea rose less than a metre.