May 22

The first Christian emperor was baptised only in his last days, at a villa near Nicomedia, by the Arian-leaning bishop Eusebius of Nicomedia. Late baptism was common: it washed away a lifetime of sins at once.

On the evening of 22 May, 5 Jumādā I 1260 in the Islamic calendar, the young merchant Siyyid ʿAli-Muhammad told his guest Mulla Husayn that he was the Báb, the “Gate” to a promised one. Baháʼís keep the night as a holy day.

The Báb’s movement, then Baháʼu’lláh’s, which most Bábís followed: one God, the oneness of humanity and a line of messengers that includes Abraham, Moses, the Buddha, Jesus and Muhammad. The Baháʼí calendar counts its years from 1844, and its world centre is in Haifa.

The decree had not yet arrived. After the arrest of an enslaved drummer named Romain, crowds rose in Saint-Pierre, and on 23 May the governor proclaimed abolition on his own authority. Martinique still marks 22 May.

General Order No. 143 set up a War Department bureau to raise Black regiments, the United States Colored Troops. By the end of the war about 179,000 Black men had served in the army, a tenth of it, and 19,000 in the navy.

Its start is a Julian date: 22 May in Russia, 4 June in the West. General Brusilov attacked along a wide front with little warning and shattered the Austro-Hungarian armies in Volhynia and Galicia, taking hundreds of thousands of prisoners. It was Russia’s greatest success of the war, and it bled…

Bad snow and exhaustion slowed the climb up the Lhotse Face for more than two weeks; George Lowe spent eleven days cutting steps up it. Hunt’s whole plan hung on getting loads to the South Col.

A Texan who played a plastic alto saxophone, with Don Cherry, Charlie Haden and Billy Higgins and no piano to fix the harmony, recorded for Atlantic in Hollywood. The title was a boast, and “Lonely Woman” made it good.

Bob Metcalfe sketched a network where every machine shares one cable, listens before sending, and backs off for a random moment when two collide. Its descendants still wire most offices and data centres.

Namco’s Toru Iwatani wanted a game without shooting that would bring women and couples into arcades full of young men; the hero, he said, was a pizza with a slice missing. It went on sale in Japan in July as Puck-Man, and Midway renamed it for North America in October, fearing vandals would turn…

A programmer in Florida, Laszlo Hanyecz, offered 10,000 bitcoins on a forum for two large pizzas, and another user had them delivered. It is the first known purchase of goods with bitcoin.