O Level World History: Depth Study A, The First World War 1914-18 (Cambridge 2147)

Depth Study A covers the First World War from the German invasion of Belgium in August 1914 to the Armistice of 11 November 1918. Cambridge O Level History (2147) organises it into four key questions: why there was stalemate on the Western Front, how far it was a world war, how important the other fronts were, and why Germany asked for an armistice in 1918. The causes of the war are not part of this Depth Study; they belong to Core Content Option A, key question 6.

Where this fits in 2147

In 2147 every candidate studies at least one of five Depth Studies. Paper 1 (2 hours, 60 marks, 55% of the O Level) has Section B, which sets two questions on each Depth Study; you answer one, in three parts – (a) 4 marks, (b) 6 marks, (c) 10 marks. Unlike the IGCSE, O Level has no coursework or Paper 4, so Paper 1 is the only place this content is examined. Related: Depth Study A revision notes, Depth Study A practice questions, and the overview O Level Depth Studies guide.

Syllabus coverage

CAMBRIDGE O LEVEL HISTORY (2147), 2024-2026 – DEPTH STUDY A: THE FIRST WORLD WAR, 1914-18

• 1 Why was there stalemate on the Western Front? Why the Schlieffen Plan failed; why a defensive war emerged by the end of 1914; living and fighting in the trenches; new methods of warfare; Verdun and the Somme.
• 2 To what extent was it a world war? British Empire troops on the Western Front (Indian and Canadian case studies); Indian and South African troops in Africa (German East Africa, South West Africa); Japan’s contribution (Tsingtao, the sea lanes); the Arab Revolt.
• 3 How important were other fronts? The war at sea (Jutland, convoys, U-boats); Gallipoli; the Eastern Front; the impact of war on civilians.
• 4 Why did Germany ask for an armistice in 1918? America’s entry; the failure of the 1918 German offensive; revolution in Germany (the Kiel Mutiny, the Kaiser’s abdication); the Armistice.

Why did the Schlieffen Plan fail?

The plan aimed to defeat France in about six weeks by sweeping through Belgium, then turn east before Russia was ready. It went wrong in four ways:

1. Belgian resistance at Liège and elsewhere slowed the advance in August 1914.
2. Britain entered the war on 4 August, partly to defend Belgian neutrality under the 1839 Treaty of London; the British Expeditionary Force delayed the Germans at Mons (23 August).
3. Russia mobilised faster than expected, so troops were moved east, weakening the right wing.
4. The Germans swung east of Paris instead of around it, and French and British counter-attacks at the Marne (September 1914) pushed them back.

Why had a defensive war emerged by the end of 1914?

After the Marne, each side tried to outflank the other in the “race to the sea”. At the First Battle of Ypres (October-November 1914) the BEF held on with heavy losses. Both sides dug in, and by December a line of trenches ran from the Channel coast to Switzerland. Defence was simply stronger than attack: machine guns, barbed wire and artillery could stop infantry crossing open ground, while railways let defenders bring up reserves faster than attackers could advance. Generals turned to attrition – wearing down the enemy’s men and resources.

What was living and fighting in the trenches like?

Soldiers rotated between front-line, support and reserve trenches. Conditions included mud, rats and lice, cold, trench foot, constant shellfire and the mental strain later called shell shock. Most time was spent on routine work, sentry duty and night raids; attacks meant going “over the top” into no man’s land under machine-gun fire.

How important were new methods of warfare?

Weapon	First major use	Effect
Machine gun	From 1914	Gave defenders a huge advantage
Poison gas	Chlorine at Ypres, April 1915; later mustard gas	Terrifying, but gas masks limited its impact
Tank	The Somme, September 1916; massed at Cambrai, November 1917	Unreliable at first; important by 1918 alongside infantry and artillery
Aircraft	Reconnaissance from 1914	Spotting for artillery; later fighters and bombers

No single weapon broke the stalemate; what changed by 1918 was the combination of artillery, tanks, aircraft and infantry tactics.

What was the significance of Verdun and the Somme?

Verdun (February-December 1916) was Falkenhayn’s attempt to “bleed France white” at a fortress France would defend at any cost; under Pétain the French held, but both sides lost hundreds of thousands of men. The Somme (1 July-November 1916) was launched partly to relieve Verdun. On the first day the British suffered about 57,000 casualties. Haig has been criticised for long preliminary bombardments that failed to cut the wire and for continuing the battle; defenders of Haig argue that the Somme did relieve Verdun, wore down the German army and taught the British lessons used in 1918.

To what extent was it a world war?

• Indian troops reached the Western Front in autumn 1914 and fought at Ypres and Neuve Chapelle (1915), in an unfamiliar climate; Khudadad Khan became the first Indian soldier to win the Victoria Cross.
• Canadian troops faced the first gas attack at Second Ypres (1915) and captured Vimy Ridge (April 1917), a defining moment for Canada.
• Africa: South African forces under Botha conquered German South West Africa by July 1915. In German East Africa, Indian troops took part in the failed landing at Tanga (1914), and South African forces under Smuts led the 1916 campaign, but Lettow-Vorbeck’s guerrilla force was not defeated and surrendered only after the Armistice.
• Japan captured the German base at Tsingtao (November 1914) and Germany’s Pacific islands, and its navy escorted Allied convoys, including in the Mediterranean.
• The Arab Revolt (from June 1916), led by Sharif Hussein of Mecca with British support and advisers such as T. E. Lawrence, took Aqaba (1917) and helped the British reach Damascus (1918), tying down Ottoman forces.

How important were the other fronts?

At sea: at Jutland (May-June 1916) Britain lost more ships and men, but the German High Seas Fleet did not seriously challenge British control again, so the blockade of Germany continued. Germany’s U-boat campaign, including unrestricted submarine warfare from February 1917, nearly starved Britain until the convoy system cut losses from mid-1917.

Gallipoli (April 1915-January 1916) aimed to knock out the Ottoman Empire and open a supply route to Russia. It failed through poor planning, the failure of the naval attack in March, strong Turkish defence led by commanders such as Mustafa Kemal, difficult terrain and disease. The Allies evacuated.

The Eastern Front was more mobile. Russia’s early defeat at Tannenberg (August 1914) and later Brusilov’s offensive (1916) drew German forces east; Russia’s collapse after 1917 led to the Treaty of Brest-Litovsk (March 1918), freeing German troops for the west.

Civilians faced conscription (in Britain from 1916), government control under DORA, food shortages and, in Germany, near-starvation in the “turnip winter” of 1916-17 because of the blockade; women took on new jobs in munitions and transport.

Why did Germany ask for an armistice in 1918?

• America’s entry (April 1917), after unrestricted U-boat warfare and the Zimmermann Telegram, promised millions of fresh troops; over a million had arrived by mid-1918.
• The German Spring Offensive (from 21 March 1918), using stormtroopers and troops freed from the east, advanced far but outran its supplies and lost its best men.
• The Allied advance from Amiens (8 August 1918, Ludendorff’s “black day”) pushed Germany back, while its allies Bulgaria, the Ottoman Empire and Austria-Hungary collapsed.
• Revolution at home: the Kiel Mutiny of sailors spread into revolution; the Kaiser abdicated on 9 November; the new government signed the Armistice at Compiègne, effective 11 a.m. on 11 November 1918.

Worked example: a (c) question

“The failure of the Spring Offensive was the main reason Germany asked for an armistice.” How far do you agree? [10]

Explain the offensive’s failure (exhausted reserves, overstretched lines), then weigh other factors (American troops and supplies; the Allied counter-offensive; the blockade and starvation; revolution and the collapse of Germany’s allies). Conclude, for example, that the offensive’s failure was the turning point because it made the Allied counter-offensive possible, but that the home front’s collapse explains the timing in November.

Common mistakes

• Writing about the causes of the war, which are not part of Depth Study A.
• Treating Jutland as a simple British defeat or victory without explaining its consequences.
• Leaving out the named case studies (Indian and Canadian troops; German East Africa and South West Africa).
• Explaining stalemate only through conditions, not through why defence was stronger.

Frequently asked questions

Is this Depth Study the same as the IGCSE 0470 one? The key questions and content are the same in the 2024-2026 syllabuses, but the O Level examines it only through Paper 1 Section B.

Which key question is most often neglected? Key question 2 (the world war); revise all its case studies.

What date ends the Depth Study? The Armistice of 11 November 1918. The peace treaties belong to Core Content Option B.

Official syllabus

Cambridge O Level History (2147) syllabus for examination in 2024, 2025 and 2026 – cambridgeinternational.org (Depth study A, focus points and specified content). Always check the current syllabus before an exam.