October 9

The emperor Frederick Barbarossa, Philip II of France and Richard I of England all took the cross; England and France paid for it with the “Saladin tithe”, a tenth of every layman’s income and movables.

A Delft draper with home-ground lenses wrote to the Royal Society of “little animals” swarming in a drop of pepper water, far too small to see. They were bacteria. The Society doubted him until Hooke saw them in 1677.

The test was to set a plainchant antiphon in strict counterpoint, alone in a locked room. His answer, K. 86, passed, though it had been quietly helped along by Padre Martini, the most respected teacher in Italy. The academy’s rules set a minimum age of twenty; he was fourteen.

The ship sailed from Plymouth four days into the war, under Frank Worsley. Shackleton stayed behind to settle the money and followed by mail steamer, joining her in Buenos Aires. He called the voyage out “uneventful”.

The charge was sabotage and conspiracy, and it carried the death penalty. Bram Fischer led the defence against the prosecutor Percy Yutar. The accused agreed not to deny what they had done, only that they had decided on guerrilla war, and to turn the trial on apartheid.

David Rumelhart, Geoffrey Hinton and Ronald Williams showed how a network with hidden layers could learn, by passing each error backwards to adjust every connection — the answer to Minsky and Papert’s objection. The method had been found before, by Seppo Linnainmaa and Paul Werbos among others;…

Hospitals had cleared beds and the security forces were armed. Some 70,000 people marched anyway, chanting “We are the people” and “No violence”, while an appeal from the conductor Kurt Masur and three local party secretaries played over the city loudspeakers. Nobody gave the order to shoot.

From Netscape's IPO — priced at $28 a share, opening at $71 — to the bottom of the crash. The Nasdaq closed at 5,048 on 10 March 2000 and lost 78% by October 2002, taking Pets.com, Webvan and hundreds more with it. Amazon and eBay made it through.

From Netscape’s flotation to the Nasdaq’s bottom. Companies with no profits and sometimes no revenue went public on a web address; adding “.com” to a firm’s name was enough to lift its shares.

Down 78 per cent from its peak, some 5 trillion dollars of market value gone.

Google paid $1.65 billion in stock for a company not yet two years old, with a few dozen employees.

Two months into the credit crunch, American shares hit their high. The Dow Jones Industrial Average would not close above it again until March 2013.

Iceland’s largest bank was the last of the three to go into state hands, within four days of Haarde’s speech. The Reykjavík stock exchange suspended trading; when it reopened the index fell 77 per cent in a day.

Half to David Baker for designing new proteins, half to Demis Hassabis and John Jumper of Google DeepMind for AlphaFold: two Nobel Prizes for AI in two days.