Title: Military history of Australia
Content:  When Britain declared war on Germany at the start of the First World War, the Australian government rapidly followed suit, with Prime Minister Joseph Cook declaring on 5 August 1914 that "...when the Empire is at war, so also is Australia" and reflecting the sentiment of many Australians that any declaration of war by Britain automatically included Australia. This was itself in part due to the large number of British-born citizens and first generation Anglo-Australians that made up the Australian population at the time. Indeed, by the end of the war almost 20% of those who served in the Australian forces had been born in Britain. As the existing 
Title: Military history of Australia during World War II
Content:  Australia entered World War II on 3 September 1939, following the government's acceptance of the United Kingdom's declaration of war on Nazi Germany. Australia later entered into a state of war with other members of the Axis powers, including the Kingdom of Italy on 11 June 1940, and the Empire of Japan on 9 December 1941. By the end of the war, almost a million Australians had served in the armed forces, whose military units fought primarily in the European theatre, North African campaign, and the South West Pacific theatre. In addition, Australia came under direct attack for the first time in its 
Title: Military history of Australia during World War I
Content:   In Australia, the outbreak of World War I was greeted with considerable enthusiasm. Even before Britain declared war on Germany on 4 August 1914, the nation pledged its support alongside other states of the British Empire and almost immediately began preparations to send forces overseas to engage in the conflict. The first campaign that Australians were involved in was in German New Guinea after a hastily raised force known as the Australian Naval and Military Expeditionary Force was dispatched from Australia to seize German possessions in the Pacific in September 1914. At the same time another expeditionary force, initially consisting of 20,000 men and known as the First 
Title: History of Australia (1901–1945)
Content:  Australia sent many thousands of troops to fight for Britain during the First World War between 1914 and 1918. Thousands lost their lives at Gallipoli, on the Turkish coast and many more in France. Both Australian victories and losses on World War I battlefields contribute significantly to Australia's national identity. By war's end, over 60,000 Australians had died during the conflict and 160,000 were wounded, a high proportion of the 330,000 who had fought overseas. Australia's annual holiday to remember its war dead is held on ANZAC Day, 25 April, each year, the date of the first landings at Gallipoli, in Turkey, in 1915, as part 
Title: Military history of Australia
Content:  19th century. In the early 20th century, as a federated dominion and later as an independent nation, Australia fought in the First World War and Second World War, as well as in the wars in Korea, Malaya, Borneo and Vietnam during the Cold War. In the Post-Vietnam era Australian forces have been involved in numerous international peacekeeping missions, through the United Nations and other agencies, including in the Sinai, Persian Gulf, Rwanda, Somalia, East Timor and the Solomon Islands, as well as many overseas humanitarian relief operations, while more recently they have also fought as part of multi-lateral forces in Iraq and Afghanistan. In total, nearly 103,000 Australians died during these conflicts.
Title: 1914 in Australia
Content:  their support. Opposition Leader Andrew Fisher states in a speech at Colac, Victoria Australians will stand beside her own to help and defend her to our last man and our last shilling. Prime Minister Joseph Cook states in Horsham, Victoria "All of our resources in Australia are ... for the preservation and the security of the empire". ; 4 August – The United Kingdom declares war on Germany – as a consequence Australia enters the war. ; 5 August – Australia fires its first shot in World War I at Fort Nepean in Victoria. The German merchant ship Pfalz was 
Title: History of Australia (1901–1945)
Content:   On 3 September 1939, the Prime Minister, Robert Menzies, made a national radio broadcast: "My fellow Australians. It is my melancholy duty to inform you, officially, that, in consequence of the persistence by Germany in her invasion of Poland, Great Britain has declared war upon her, and that, as a result, Australia is also at war." Thus began Australia's involvement in the six-year global conflict. Australians were to fight in an extraordinary variety of locations, from withstanding the advance of Hitler's Panzers in the Siege of Tobruk; to turning back the advance of the Imperial Japanese Army in the New Guinea Campaign. From bomber 
Title: History of Australia
Content:  When the United Kingdom declared war on Germany on 4 August 1914, the declaration automatically involved all of Britain's colonies and dominions. The outbreak of war came in the middle of the 1914 federal election campaign during which Labor leader Andrew Fisher promised to defend Britain "to the last man and the last shilling." Both major parties offered Britain 20,000 Australian troops. As the Defence Act 1903 precluded sending conscripts overseas, a new volunteer force, the Australian Imperial Force (AIF), was raised to meet this commitment. Public enthusiasm for the war was high, and the initial quota for the AIF was quickly filled. The troops left for Egypt on 1 November 1914, 
Title: Australian Army during World War I
Content:  The Australian Army was the largest service in the Australian military during World War I. The First Australian Imperial Force (AIF) was the Army's main expeditionary force and was formed from 15 August 1914 with an initial strength of 20,000 men, following Britain's declaration of war on Germany. Meanwhile, the separate, hastily raised 2,000-man Australian Naval and Military Expeditionary Force (AN&MEF), landed near Rabaul in German New Guinea on 11 September 1914 and obtained the surrender of the German garrison after ten days; it later provided occupation forces for the duration of the war. In addition, small military forces based on the pre-war Permanent Forces and part-time Citizen Forces were maintained in Australia to defend the country from attack. 
Title: History of Australia
Content:   On 3 September 1939, the Prime Minister, Robert Menzies, made a national radio broadcast: "My fellow Australians. It is my melancholy duty to inform you, officially, that, in consequence of the persistence by Germany in her invasion of Poland, Great Britain has declared war upon her, and that, as a result, Australia is also at war." Thus began Australia's involvement in the six-year global conflict. Australians were to fight in an extraordinary variety of locations, from withstanding the advance of Hitler's Panzers in the Siege of Tobruk; to turning back the advance of the Imperial Japanese Army in the New Guinea Campaign. From bomber missions over 

Question: who did australia fight in the first world war?
Answer: United Kingdom.