1 januari

The old calendar had drifted about three months out of step with the seasons. To reset it Caesar made 46 BCE 445 days long; from 1 January 45 the year had 365 days and a leap day every fourth year. Trimmed in 1582, it is the calendar used today.

To end the drift, 46 BCE was stretched to 445 days, and from 1 January 45 Rome counted 365¼ days on the Egyptian model. Pliny credits the Alexandrian astronomer Sosigenes. Every date from here on is the one Romans wrote down.

At the royal family’s public dinner, the grand couvert, Wolfgang stood next to the Queen all evening, chatting and eating what she handed him from the table. Marie Leszczyńska spoke German; Louis XV did not, so she translated for him.

The violinist and impresario Johann Peter Salomon brought Haydn over for the seasons of 1791–92 and 1794–95; in between he was back in Vienna. He wrote twelve symphonies, Nos. 93 to 104, for London, and Oxford made him a Doctor of Music.

Owen took over his father-in-law David Dale’s mills on the Clyde and ran them as an experiment: no children under ten at work, shorter hours, a village shop at fair prices and a school. The mills still made a profit, and visitors came from across Europe. In 1825 he left for America to found New…

Dessalines gave the country its Taíno name. It was the first state founded by people who had freed themselves from slavery. In 1825 France made Haiti pay 150 million francs for recognition, later cut to 90 million.

The Haitian RevolutionSaint-Domingue

Saint-Domingue, the richest colony in the world, held about half a million enslaved people. On the night of 22 August 1791 they rose on the northern plain and burned the plantations. Twelve years of war against planters and against Spanish, British and French armies ended with the only successful…

Jefferson had signed the act in March 1807; it took effect on the first day the Constitution allowed. Enforcement was weak, and the trade in people within the United States grew as cotton spread west.

Its infant school, for children from about two, is often called the first in Britain. Owen wanted no punishments and no books for the youngest: they were taught with pictures, maps, singing and dancing.

John Tawell poisoned his mistress near Slough and caught the train to London. The station telegraphed ahead that he was “in the garb of a KWAKER” — the needle telegraph had no Q — and a policeman followed him from Paddington. He was hanged in March; the wires, said the papers, had hanged him.

Everyone enslaved in the rebel states “are, and henceforward shall be free”. It exempted the loyal border states and Union-held areas, so it freed few people that day, but every advance of the army now freed more. It also opened the army to Black soldiers.

A decree of 9 December 1872 announced that the 3rd day of the 12th month of Meiji 5 would be 1 January 1873. The old year lost its last four weeks, and the government saved a month’s salaries, since the lunar year 1873 would have had thirteen.

At the mouth of the Río Grande, where the canal’s Pacific entrance would be, de Lesseps’s young daughter Ferdinande struck a pickaxe into a champagne case filled with earth, after the party had steamed out to the site on a tender.

Three and a half years with the Żorawski family, who managed a sugar-beet works on the plains north of Warsaw. With the eldest daughter she ran a secret class teaching village children to read and write Polish, which could have meant deportation to Siberia. In the evenings she taught herself…

An ordinance drafted by Alderman Sidney Story confined legal prostitution to a district behind the French Quarter, which took his name, to his dismay. Its “Blue Books” listed the women by race. Pianists such as Jelly Roll Morton played its parlours, but most bands played dance halls, parks and…

The first Oz book, written by L. Frank Baum and illustrated in colour by W. W. Denslow. Baum's introduction, dated Chicago, April 1900, says it was written “solely to please children of today”, a modernized fairy tale from which “the heartaches and nightmares are left out”. Nothing in it says when…

Dorothy’s first visit crosses the whole of Oz from the Munchkin Country in the east to the Winkie Country in the west, and ends in the south at Glinda’s castle.

Baum's second Oz book, and the first illustrated by John R. Neill, who drew every Oz book after it. In his note, dated Chicago, June 1904, Baum says he wrote it because children kept asking for “the Scarecrow and the Tin Woodman”, and a girl called Dorothy had made him promise. It introduces Tip,…

Between March and September a clerk with no university post finished a doctoral thesis and sent Annalen der Physik four papers: on light quanta, Brownian motion, relativity and E = mc². He wrote them at home in Bern’s old town and, when he could, at his desk in the patent office. Each paper…

Dorothy arrives from the sea on the far side of the desert and crosses back into Oz with Ozma, by way of the Nome King’s caverns.

The third Oz book is the first in which Dorothy goes back to Oz, and the first set outside it, in the Land of Ev across the desert. Baum's full title promises “a record of her adventures with Dorothy Gale of Kansas, the Yellow Hen, the Scarecrow, the Tin Woodman, Tiktok, the Cowardly Lion, and the…

Dorothy reaches Oz this time from California, through a crack in the earth, and the Wizard of Oz comes back with her. Baum's introduction explains why the book is about a girl, a boy and a kitten rather than the Scarecrow: the children who wrote to him asked for the Wizard. The underground…

Dorothy’s third visit starts in California and runs through the earth to the Vegetable Kingdom at the right-hand edge of the map, and up again to the Emerald City.

Dorothy’s fourth visit starts in Kansas and takes the road: down through the Scoodlers’ country and across the desert by sand-boat into the Winkie Country.

Dorothy sets out from the Kansas farm with a tramp and a lost boy and never meets a cyclone: she walks, and the road is what takes her to Oz. The book gathers the Shaggy Man, Button-Bright and Polychrome, and ends with Ozma’s birthday party, which draws guests from fairylands all over the world.

Dorothy’s fifth visit is the last: the whole family moves to Oz, and Oz is closed.

Baum meant this sixth book to be the last. Two plots run side by side through it: Dorothy’s family comes to live in Oz, and the Nome King plans to destroy it. Baum’s author’s note says it is “by L. Frank Baum and his correspondents”, since many of its ideas came from readers’ letters. The last…

After 1910’s “last” book, Baum reopened Oz with a prologue that explains how: the Royal Historian rigs a wireless tower and Dorothy replies. The quest runs from the Munchkin Country through the Emerald City and the Quadling Country to the Winkie Country, and stars a boy, Ojo, and a girl made from…

The St. Petersburg–Tampa Airboat Line flew one passenger at a time across Tampa Bay in a Benoist flying boat, in 23 minutes instead of a day by rail. The first seat went at auction for $400 to Abram Pheil, a former mayor of St. Petersburg. The line lasted four months.

The eighth book is the one whose first edition carried Neill’s “Map of the countries near to the Land of Oz”, the map under this timeline’s map view. Baum’s foreword says it tells of Ann Soforth, Queen of Oogaboo, “whom Tik-Tok assisted in conquering our old acquaintance, the Nome King”, and of…

Baum dedicates the ninth book to the Uplifters of Los Angeles and explains in “’Twixt You and Me” that children had insisted Trot and Cap’n Bill be admitted to Oz. They arrive by way of a whirlpool, a talking Ork and the kingdom of Jinxland, where no one has ever visited from Oz; it is the…

Baum’s own introduction calls it “a story with a boy hero, and a boy of whom you have never before heard”. It was written years before it appeared, and most of it takes place beyond the desert, on the Nonestic Ocean at the top right of Neill’s map; Oz arrives only in the last third, when Dorothy…

Baum dedicates this book to his granddaughter Ozma Baum, and says its main idea came from a girl of eleven who told him: “I s’pose if Ozma ever got lost, or stolen, ev’rybody in Oz would be dreadful sorry.” It is the first Oz book written as a mystery, and every character from Dorothy to the…

In “To My Readers” Baum says many correspondents had asked “what ever became of the ‘pretty Munchkin girl’” the Tin Woodman had been engaged to marry before the Wicked Witch enchanted his axe. This is the book that answers it, with a boy named Woot, a tin soldier and a man made of the Tin…

Baum died on 6 May 1919, and this thirteenth book appeared that year. His note “To My Readers” says the “events which have taken place in the last few years in our ‘great outside world’” were so marvellous that he could not hope to equal them, yet “The Magic of Oz” is “really more strange and…

The fourteenth and last Oz book that Baum wrote appeared in 1920, after his death in 1919. The full title promises “the Exciting Experiences of Princess Ozma of Oz, and Dorothy, in their hazardous journey to the home of the Flatheads, and to the Magic Isle of the Skeezers”, and how Glinda rescued…

Four scholars who had left the mainland, Tang Junyi, who drafted it, Mou Zongsan, Xu Fuguan and Zhang Junmai, published in Hong Kong a declaration that Confucian thought was a living philosophy, not a museum piece. It is the charter of New Confucianism.

Fifteen songs, chosen by Epstein, in one session, after a ten-hour drive through snow. A month later Decca said no and signed Brian Poole and the Tremeloes, who had auditioned the same day and lived nearer London. Epstein wrote that he was told guitar groups were on the way out and pinned it on…

Flag day: every host on the ARPANET had to move to the new protocols at once or be cut off. It is the closest thing the internet has to a birthday.

On a “flag day” every host had to adopt the protocols Vint Cerf and Robert Kahn had described in 1974, which let different networks join into one. The internet still runs on them.

Eleven countries locked their exchange rates for good and handed monetary policy to the European Central Bank. For three years the euro existed only in accounts; the old notes and coins stood in for it.

At midnight twelve countries began to swap marks, francs, lire and guilders for euros, the largest cash changeover in history. Within two months the old currencies had stopped being legal tender.

The five years in which the Kyoto targets counted. Canada withdrew in December 2011, effective a year later. The biggest emitters, the United States and China, had no targets, and world emissions kept rising.

The Doha Amendment extended Kyoto for fewer countries. It needed 144 acceptances to come into force, and did so on 31 December 2020, the last day of the period it governed.

The most distant object ever explored: a reddish, flattened snowman, two lobes that came together gently when the planets were forming.