Main Causes of World War One :

Militarism

In the 19th century Britain was the greatest sea power in the world

In 1906, a new, all improved battleship was released by Britain, the HMS Dreadnought.

In 1908, Germany launched a similar battleship called the Nassau

A naval race was underway

Germany announced she was going to build 12 more Nassau over the next 4 years

Britain built 8 new dreadnoughts in 1909

By the time war broke out, Britain had 22 dreadnought

By the time war broke out, Germany had 15 Nassau

Germany also developed other aspects of their military, having the best trained and best equipped army of 2.2 million men

Despite his, they still feared Russia's vast reserves of Manpower, the 'Russian Steamroller'

Alliances

In the decade before war, many treaties were signed

This essentially creates two rival alliances of great powers in Europe

Triple Entende (1914)

Triple Alliance (1907)

Germany

Austria-Hungary

Italy

Russia

Britain

France

Sense of protectionism and alliance to Serbia and other Slavic speaking countries, due to pan-slavism

Italy backed out of triple alliance before war started to maintain good relations with France

Increasing fear of 'encirclement' and having to fight a war on two fronts against France and Russia

Feared further attack to their eastern frontier, due to having been invaded by Germany in the Franco-Prussian war of 1871

Existence of two great rival alliances increased security fears for every country

Imperialism

Some European countries had vast, wealthy empires, while others wanted to create empires

Britain had the largest empire: New Zealand, India, Australia, Canada, and much of Africa

Germany felt it had missed out on the scramble for Africa, and wanted Germany to build an empire and be recognized as a major power

These expansionist policies and imperial rivalry lead contributed to further tensions in Europe

German Kaiser also made a speech stating that he wanted to expand his navy prowess and ensure that 'our place in the sun shall remain undisputed"

Nationalism

Strong Nationalism in the Balkans, as many wished to be free from imperialist rule by the Austro-Hungarian empire.

Man Slavic groups wished to break away and have their own nation- Panslavism

German Nationalism was a new sensation

This sentiment strong in Serbia

In the Russian empire alone, there were 80 minority groups

Result of the unification of Germany in 1871, obsessed with imperial expansion, and emulating the British empire