23 de abril

On Good Friday, Brian Boru, high king of Ireland, fought the king of Leinster and his Norse allies from Dublin, Orkney and the Isles. Brian’s side won, but Brian was killed in his tent, with his son and grandson. Later legend made it Ireland’s war against the Vikings; it was as much an Irish civil…

Before a royal notary at Amboise, on Easter Eve. Melzi, the executor, received the books, instruments and drawings; Salaì and the servant Battista de Vilanis each half the Milan vineyard; his half-brothers money in Florence. Sixty poor men were to carry candles at his funeral.

He died, probably at New Place, and was buried in the chancel of Holy Trinity on 25 April. His 23 April was 3 May in the Gregorian calendar, ten days after the 23 April on which Cervantes was buried in Madrid. Good frend for Iesvs sake forbeare, / To digg the dvst encloased heare — his gravestone

Washington wanted the escaped enslaved returned; the British commander, Sir Guy Carleton, refused and instead had about 3,000 names recorded, of Black Loyalists leaving New York for Nova Scotia and elsewhere. One was Harry Washington, who had escaped from Mount Vernon.

Edmund Burke led the Commons’ case against the first Governor-General for corruption and cruelty in India; Londoners paid for tickets to the opening days in Westminster Hall. The trial dragged on for seven years, and the Lords acquitted him on every charge. The costs ruined him.

His eldest daughter, aged ten, died at Malvern where he had taken her for the water cure. Emma, heavily pregnant, stayed at home. Darwin wrote a memoir of her a week later: “We have lost the joy of the household, and the solace of our old age”. After Annie, he later said, he gave up Christianity.

With Istanbul under Allied occupation, deputies met in an unfinished Unionist club in Ankara and claimed to be the nation’s government. Mustafa Kemal was elected its president.

Germany’s “uranium club” first met at the Reich Education Ministry in April 1939; the Army Ordnance Office took it over when the war began. Its physicists, Heisenberg among them, built reactors with heavy water as moderator, but never a self-sustaining chain reaction and never a bomb programme.

US health secretary Margaret Heckler announced that Robert Gallo’s laboratory had found the cause of AIDS, and promised a vaccine “ready for testing in approximately two years”. It was the French virus under another name; a 1987 agreement split the credit, and in 1986 both were renamed HIV.

Michael Mann, Raymond Bradley and Malcolm Hughes combined tree rings, corals, ice cores and old records into six centuries of northern temperatures; a 1999 sequel reached back to AD 1000. The shape, a long flat shaft and a sharp 20th-century blade, became one of the most attacked graphs in…

“Me at the zoo”: 19 seconds of co-founder Jawed Karim in front of the elephants. Google bought YouTube 18 months later for $1.65 billion.

The first video on YouTube: 19 seconds of co-founder Jawed Karim in front of the elephants. The site was a few months old, built by three former PayPal employees who wanted a place to share video without emailing files.

Named at the Okpo yard by South Korea’s first lady, with the president watching, the ship carried 23,964 TEU on a hull of almost 400 metres.