He returned to the Western Front in early 1916 as a general staff officer in the 33rd Division and took part in the Battle of Arras in April / May 1917.

In April 1917, when German U-boats were sinking many British ships with torpedoes, the marine artist Norman Wilkinson devised dazzle camouflage, which paradoxically made ships more visible but harder to target.

A meeting called by Count Plunkett on 19 April 1917 led to the formation of a broad political movement under the banner of Sinn Féin which was formalised at the Sinn Féin Ard Fheis of 25 October 1917.

Among the more than two dozen exhibitors who attended the first meeting held in New York on April 25, 1917, were Frederick Dahnken of the Turner and Dahnken Circuit in San Francisco, Harry O. Schwalbe of Philadelphia, Samuel Roxy Rothafel of New York, Earl H. Hulsey of Dallas and Nathan H. Gordon of Boston.

In April 1917, during a brief period of German aerial supremacy, a grandstanding Member of Parliament ( upset at the lack of orders for his own aircraft manufacturing firm ) claimed that, on the Western Front, a British pilot's average life expectancy was 93 flying hours, or about three weeks of active service.

To that end, they had arranged for the safe conduct of Lenin and his comrades from exile in Switzerland to Petrograd in April 1917, and financed the Bolshevik party, believing Lenin to be the most powerful weapon they could use against Russia.

Hawks left Cornell in April 1917 when the United States declared war on Germany and entered World War I.

Before Hawks was called for active duty, he took the opportunity to go back to Hollywood and by the end of April 1917 was working on Cecil B. DeMille's The Little American, where he met and befriended the then eighteen-year-old slate boy James Wong Howe.

The United States joined with the Allies in April 1917.

After the United States entered the war in April 1917, President Woodrow Wilson appointed Hoover to head the U. S. Food Administration.

Ieoh Ming Pei ( born April 26, 1917 ), commonly known as I. M. Pei, is a Chinese American architect, often called a master of modern architecture.

Ieoh Ming Pei was born on April 26, 1917 to Tsuyee Pei and Lien Kwun, and the family moved to Hong Kong one year later.

In April 1917, he was arrested again but managed to escape and participate in the July Days demonstrations in Petrograd ( St. Petersburg ) on 16 – 17 July 1917.

Hubbard's father rejoined in the Navy in April 1917, during World War I, while his mother May worked as a clerk for the state government.

December 15, 1859 – April 14, 1917 ) was a Polish doctor, linguist, and the creator of Esperanto, the most successful constructed language designed for international communication.

Zamenhof died in Warsaw on April 14, 1917, and is buried in the Okopowa Street Jewish Cemetery in that city.

In April 1917, Lenin published the April Theses, the strategy of the October Revolution, which proposed that the Russian revolution was not an isolated national event, but a fundamentally international event — the first world socialist revolution.

* The Tasks of the Proletariat in the Present Revolution ( The " April Theses "), 1917

Mao would publish his first article, " A Study of Physical Culture ", in New Youth in April 1917, in which he instructed all Chinese people to increase their physical strength in order to serve the revolutionary cause.

In January 1917 Newman took up a teaching post at Archbishop Holgate's Grammar School in York, leaving in April 1918.

In April 1922, Mitchell was seeing two men almost daily ; one was Berrien “ Red ” Upshaw, whom she is thought to have met in 1917 at a dance hosted by the parents of one of her friends, and the other, Upshaw's roommate and friend, John R. Marsh, a copy editor from Kentucky who worked for the Associated Press.

As a means to destabilize Russia on the Eastern Front, Germany's High Command allowed Lenin to travel across Germany and German-held territory into Russia in April 1917, anticipating him partaking in revolutionary activity.

During the Western Allied invasion of Germany in April 1945, the airfield was seized by the United States Third Army, and used by the USAAF 354th Fighter Group which flew P-47 Thunderbolts from the aerodrome ( designated ALG R-82 ) from late April until the German capitulation on 7 May 1945.

Carl Friedrich Gauss was born on 30 April 1777 in Braunschweig ( Brunswick ), in the Duchy of Braunschweig-Wolfenbüttel, now part of Lower Saxony, Germany, as the son of poor working-class parents.

That council was called by John XXIII and was held from 16 November 1414 to 22 April 1418 in Constance, Germany.

Edmund Gustav Albrecht Husserl (; April 8, 1859, Proßnitz, Moravia, Austrian Empire – April 26, 1938, Freiburg, Germany ) was a philosopher and mathematician and the founder of the 20th century philosophical school of phenomenology.

Plunkett had travelled to Germany in April 1915 to join Roger Casement.

In April 2008, following the 2008 Hamburg state election, the Green-Alternative List ( GAL ) in Hamburg entered into a coalition with the Christian Democratic Union ( CDU ), the first such state-level coalition in Germany.

The ruling Communist party, known as the " Socialist Unity Party " ( SED ), was formed in April 1946 from the merger between the German Communist Party ( KPD ) and the Social Democratic Party of Germany ( SPD ) by mandate of Joseph Stalin.

Himmler declared himself the provisional leader of Germany, telling Bernadotte on 23 April that Hitler would be dead within the next few days.

The Allied ground advance into Germany reached Hanover in April 1945.

Ian Ashley Murdock was born in Konstanz, West Germany on April 28, 1973.

In an effort to demonstrate peaceful intentions toward Germany, on 13 April 1941, Stalin oversaw the signing of a neutrality pact with Axis power Japan.

By April 1945, Nazi Germany faced its last days with 1. 9 million German soldiers in the East fighting 6. 4 million Red Army soldiers while 1 million German soldiers in the West battled 4 million Western Allied soldiers.

Ulrich Friedrich Wilhelm Joachim von Ribbentrop ( 30 April 1893 – 16 October 1946 ) was Foreign Minister of Germany from 1938 until 1945.

On 17 April 1934, French Foreign Minister Louis Barthou issued the so-called " Barthou note " which led to concerns on the part of Hitler that the French would ask for sanctions against Germany for violating Part V of the Versailles treaty.

By April 1938, Ribbentrop had ended all German arms shipments to China and had all of the German Army officers serving with the Kuomintang government of Chiang Kai-shek recalled ( with the threat that the families of the officers in China would be sent to concentration camps if the officers did not return to Germany immediately ).

In April 1939, when Ribbentrop announced at a secret meeting of the Foreign Office's senior staff that Germany was ending talks with the Poles and was instead going to destroy Poland in an operation late that year, the news was greeted joyfully by those present.

In April 1939, Ribbentrop received intelligence that Britain and Turkey were negotiating an alliance intended to keep Germany out of the Balkans.

The French government then proposed that France, West Germany and Italy jointly develop and produce nuclear weapons and delivery systems, and an agreement was signed in April 1958.

The Allied ground advance into Germany reached Leipzig in late April 1945.

On 16 April 1922, Germany and the Soviet Union entered the Treaty of Rapallo, pursuant to which they renounced territorial and financial claims against each other.

In an effort to demonstrate peaceful intentions toward Germany, on 13 April 1941, the Soviets signed a neutrality pact with Axis power Japan.