Declarations Of War timeline

Germany Declares War on Portugal

Despite its old alliance with Britain, Portugal did not form a part of the system of alliances which became enemies in World War I and thus kept... Read more

Austria-Hungary Declares War on Portugal

The deaths of Franz Joseph's brother, Maximilian (1867), and only son, Rudolf, made the Emperor's nephew, Franz Ferdinand, heir to the crown. On... Read more

Romania Declares War on Austria-Hungary

The Romanian people rather inclined toward the side of the Allies from the beginning of the War, but they were prevented from following their... Read more

Italy Declares War on Germany

The Italian campaign refers to a series of battles fought between the armies of Austria-Hungary and Italy, along with their allies, in northern... Read more

Turkey Declares War on Romania

The Romanian Campaign was a campaign in the Balkan theatre of World War I, with Romania and Russia allied against the armies of the Central... Read more

Bulgaria Declares War on Romania

In 1915 Lieutenant-Colonel Christopher Thompson, a fluent French speaker, was sent to Bucharest as British military attaché on Kitchener's... Read more

United States Declares War on Germany

DECLARATION OF WAR Public Resolution No. 1 S. J. Res. 1 65th Congress Sixty-fifth Congress of the United States of America; At the First... Read more

Panama Declares War on Germany

Our indisputable duty in this tremendous hour of history is of a common ally, whose interests and existence as well are linked indissolubly with... Read more

Cuba Declares War on Germany

Resolved, that from today a state of war is formally declared between the Republic of Cuba and the Imperial Government of Germany, and the... Read more

Greece Declares War on Austria-Hungary, Bulgaria, Germany and Turkey

As a result of the Balkan Wars, Greece successfully increased the extent of her territory and population, a challenging context both socially and... Read more

Siam Declares War on Germany and Austria-Hungary

In 1917 Siam declared war on Germany, mainly to gain favour with the British and the French. Siam's token participation in World War I secured it a... Read more

China Declares War on Austria-Hungary

On August 14th China formally joined the Allies and declared war on Austria and Germany. She took no great part in the war, except to invade the... Read more

China Declares War on Germany

On August 14th China formally joined the Allies and declared war on Austria and Germany. She took no great part in the war, except to invade the... Read more

Brazil Declares War on Germany

Despite the then internal political conditions, Brazil entered into World War I in 1917, alongside with the Triple Entente, after initially... Read more

United States Declares War on Austria-Hungary

Theatre definitions: Western Front comprises the Franco-German-Belgian front and any military action in Great Britain, Switzerland, Scandinavia... Read more

Panama Declares War on Austria-Hungary

The Central American and Caribbean republics were officially pro-Ally. Of course Panama and Cuba were treaty protectorates, and Haiti, the... Read more

Guatemala Declares War on Germany

Like Tinoco, Guatemalan President Estrada Cabrera had his own reasons for declaring war on Germany. Over the previous twenty years Germany had... Read more

Nicaragua Declares War on Germany and Austria-Hungary

The Dominican Republic, then still known as Santo Domingo, had been occupied by U.S. Marines since late 1916 and thus its government was obliged to... Read more

Costa Rica declares War on Germany

Of course, these levels of 'involvement' differed hugely. Some countries mobilized millions of troops and fought hard for over four years, some... Read more

Haiti Declares War on Germany

A month after the United States declared war Haitian President Sudre Dartiguenave asked the Haitian Congress for a declaration of war because of... Read more

Honduras Declares War on Germany

Honduran President Francisco Bertrand followed the United States' lead and broke relations at the same time Nicaragua did. In July 1918 it became... Read more