March 13

A Moroccan army of about four thousand, led across the Sahara by the Spanish-born Judar Pasha, broke Askia Ishaq II’s far larger host with arquebuses and cannon. Gao, Timbuktu and Jenne fell, and Songhai broke apart.

From Gao on the Niger bend, Songhai overtook Mali to become the largest state in West African history. Its chronicles, the Tarikh al-Sudan and Tarikh al-Fattash, were written by Timbuktu scholars.

The Starry Messenger: mountains on the Moon, countless stars in the Milky Way and Jupiter’s moons, in 60 pages of Latin. The printing of 550 copies was soon sold out.

Galileo’s report was printed in Venice, but few could check it: most spyglasses on sale were too poor to show Jupiter’s moons. Kepler could only confirm them that August, with a telescope Galileo had sent to the Elector of Cologne.

Martín de Ursúa had a war galley built on the lakeshore and rowed it at the island city that morning. After a short fight the Itza fled, swimming for the far shore, and the last independent Maya kingdom was taken. Kan Ek’ was captured days later; the town of Flores stands on the site.

It took the Spanish 173 years to conquer the Maya; the Aztec capital fell two years after Cortés landed. With no single capital to seize, every Maya kingdom had to be taken on its own.

It rounded the Sun on 13 March, 32 days before Clairaut’s date and inside his margin. Newton’s gravity held for a body that went far beyond the planets and came back. Nicolas-Louis de Lacaille named it Halley’s Comet.

The last visit, for the second Milan carnival opera. Leopold stretched the stay by pleading rheumatism while he chased a post in Florence. None came, and Wolfgang never went back to Italy.

An organist who ground his own mirrors, William Herschel was sweeping the sky with a seven-foot reflector of 6.2 inches when one “star” showed a disc. He reported a comet. It was the first planet found since antiquity, and George III made him the King’s Astronomer.

On the first evening Viet Minh guns firing from the hillsides took the strongpoint Béatrice; Gabrielle fell the next night, and after that the airstrip was out of use. The garrison, reinforced by parachute to about 16,000 men, held on for 56 days on supplies dropped from the air. Washington…

A ferry sinking in a 1954 typhoon, which killed more than a thousand people, pushed Japan to tunnel from Honshu to Hokkaido. At 53.85 kilometres it was the longest railway tunnel in the world, 23.3 kilometres of it under the seabed. Thirty-four workers died building it.

ALMA is inauguratedAtacama Large Millimeter Array

66 antennas on the Chajnantor plateau, 5,000 metres up, working as one. Two 28-wheeled transporters, Otto and Lore, carry them around to reshape the array. It sees the cold gas and dust where stars and planets are born.

Three games down, Lee found a wedge in the centre that AlphaGo had not foreseen, and the program fell apart. It was the only game a human won against AlphaGo in a public match.