April 22

A chain across the Golden Horn kept the Ottoman fleet out, so Mehmed had about seventy ships hauled on greased rollers over the hill behind Galata and launched into the harbour behind the chain.

A boom closed the Golden Horn, so Mehmed had about seventy ships dragged on greased runners over the hill behind Galata and launched them inside the harbour. The defenders had to spread thin along a second front.

A fleet of 13 ships bound for India swung wide into the Atlantic and sighted Monte Pascoal. Pero Vaz de Caminha's letter to the king is called Brazil's birth certificate. Weeks later four ships sank off the Cape, and Bartolomeu Dias drowned with one of them.

Forty cantos of knights, sorceresses and a flight to the Moon to fetch Orlando’s lost wits, written for the Este court. Ariosto kept revising; the final version of 1532 has 46 cantos.

Eleven ships, about 500 soldiers and 16 horses, sent from Cuba without the governor’s blessing. They landed on Good Friday. To escape the governor’s authority, Cortés founded a town, Villa Rica de la Vera Cruz, and had its council make him captain.

Nobody could fix where the Tordesillas line fell on the far side of the world, so Charles V sold his claim to the Moluccas to Portugal for 350,000 ducats. Spain took the Philippines anyway.

He played the organ of the Thomaskirche, where Bach had been cantor. By Friedrich Rochlitz’s later and not always reliable account, the choir sang him Bach’s motet Singet dem Herrn, and Mozart called out “Here is something one can learn from!”

With no trade left, the Company was a government contractor: its directors ran India under the Board of Control and its shareholders lived on a dividend charged to Indian taxpayers.

From Plassey to the end of its trade the Company was both a business and a state: it taxed, judged and made war, while still paying dividends to shareholders in London. Parliament spent these decades deciding who should really be in charge.

Towards evening the Germans opened thousands of cylinders and let the wind carry a cloud of chlorine onto French territorial and Algerian colonial troops north of Ypres. They broke; Canadians held the flank. Within months both sides were using gas.

Davis brought sketches, not finished tunes, to a converted church on East 30th Street. With Coltrane, Cannonball Adderley, Bill Evans (Wynton Kelly on “Freddie Freeloader”), Paul Chambers and Jimmy Cobb he recorded five pieces in two sessions, nearly all of them in the first complete take.

“To the Beat Y’All: Breaking Is Hard to Do”, in the Village Voice, with Martha Cooper’s photographs, was the first serious press the dance received. Within two years the Rock Steady Crew were on film sets and touring Europe, and “breakdancing” was a word the whole world knew.