The Great Retreat, also known as the Retreat from Mons, is the name given to the long withdrawal to the River Marne, in August and September 1914, by the British Expeditionary Force (BEF) and the French Fifth Army, Allied forces on the Western Front in World War I, after their defeat by the Imperial German armies at the Battle of Charleroi (21 August) and the Battle of Mons (23 August).
 A counter-offensive by the Fifth Army, with some assistance from the BEF at the First Battle of Guise (Battle of St. Quentin 29–30 August), failed to end the German advance and the Franco-British retreat continued to and beyond the Marne.
 From 5–12 September, the First Battle of the Marne ended the Allied retreat and forced the German armies to retire towards the Aisne river and fight the First Battle of the Aisne (13–28 September).
 Reciprocal attempts to outflank the opposing armies to the north followed, known as the Race to the Sea (17 September – 17 October).
Henri Mathias Berthelot (1861–1931) was a French general during World War I.
 He held an important staff position under Joseph Joffre, the French commander-in-chief, at the First Battle of the Marne, before later commanding a corps in the front line.
 In 1917 he helped to rebuild the Romanian Army following her disastrous defeat the previous autumn, then in summer 1918 he commanded French Fifth Army at the Second Battle of the Marne, with some British and Italian troops under his command.
 In the final days of the war he again returned to Romania, and then briefly commanded French intervention forces in southern Russia in the Russian Civil War.
The Second Battle of the Marne (French: "Seconde Bataille de la Marne" ), or "Battle of Reims" (15 July – 6 August 1918) was the last major German offensive on the Western Front during the First World War.
 The attack failed when an Allied counterattack by French and American forces, including several hundred tanks, overwhelmed the Germans on their right flank, inflicting severe casualties.
 The German defeat marked the start of the relentless Allied advance which culminated in the Armistice with Germany about 100 days later.
The Battle of Wörth, also known as the Battle of Reichshoffen or as the Battle of Frœschwiller, refers to the second battle of Wörth, which took place on 6 August 1870 in the opening stages of the Franco-Prussian War.
 (The first Battle of Wœrth occurred on 23 December 1793 during the Napoleonic Wars.)
 In the second battle, troops from Germany commanded by Crown Prince Frederick and directed by his Chief of Staff, General Leonhard Graf von Blumenthal, defeated the French under Marshal Mac-Mahon near the village of Wœrth in Alsace, on the Sauer River, 10 km north of Haguenau.
The Battle of the Ch'ongch'on River, also known as the Battle of the Ch'ongch'on () or the Second Phase Campaign Western Sector (), was a decisive battle in the Korean War, and it took place from November 25 to December 2, 1950, along the Ch'ongch'on River Valley in the northwestern part of North Korea.
 In response to the successful Chinese First Phase Campaign against the United Nations forces, General Douglas MacArthur launched the Home-by-Christmas Offensive to evict the Chinese forces from Korea and to end the war.
 Anticipating this reaction, the Chinese People's Volunteer Army Commander Peng Dehuai planned a counteroffensive, dubbed the "Second Phase Campaign", against the advancing UN forces.
The Battle of the Marne (French: Première bataille de la Marne , also known as the Miracle of the Marne, "Le Miracle de la Marne") was a World War I battle fought from 6–10 September 1914.
 It resulted in an Allied victory against the German armies in the west.
 The battle was the culmination of the German advance into France and pursuit of the Allied armies which followed the Battle of the Frontiers in August and had reached the eastern outskirts of Paris.
 A counter-attack by six French armies and the British Expeditionary Force (BEF) along the Marne River forced the Imperial German Army to retreat north-west, leading to the First Battle of the Aisne and the Race to the Sea.
 The battle was a victory for the Allies but led to four years of trench warfare stalemate on the Western Front.
The Third Battle of Seoul, also known as the Chinese New Year's Offensive, the January–Fourth Retreat (Korean: 1•4 후퇴 ) or the Third Phase Campaign Western Sector (), was a battle of the Korean War, which took place from December 31, 1950 to January 7, 1951 around the South Korean capital of Seoul.
 In the aftermath of the major Chinese victory at the Battle of the Ch'ongch'on River, the United Nations Command started to contemplate the possibility of evacuation from the Korean Peninsula.
 Upon learning of this development, China's Chairman Mao Zedong ordered the Chinese People's Volunteer Army to cross the 38th parallel in an effort to pressure the United Nations forces to withdraw from South Korea.
Battle of Albert (21–23 August 1918) was the third battle by that name fought during World War I, following the First Battle of Albert and the Second Battle of Albert, with each of the series of three being fought roughly two years apart.
 This smaller third battle was significant in that it was the opening push that would lead to the Second Battle of the Somme and involved the Australian Corps.
 This attack opened the advance, with the main attack being launched by the Third Army along with support from the Fourth Army.
 The Second Battle of Bapaume, from 25 August to 3 September, was a continuation of this battle.
The Battle of Wawon (Turkish: "Kunuri Muharebeleri" ), also known as the Battle of Wayuan (), was a series of delay actions of the Korean War that took place from November 27–29, 1950 near Wawon in present-day North Korea.
 After the collapse of the US Eighth Army's right flank during the Battle of the Ch'ongch'on River, the Chinese 38th Corps advanced rapidly towards the critical road junction at Kunu-ri in an effort to cut off United Nations forces' retreat route.
 In what was considered to be Turkey's first real combat action since the aftermath of World War I, the Turkish Brigade attempted to delay the Chinese advances at Wawon.
 Although during the battle the Turkish Brigade was crippled after being encircled by Chinese forces with superior numbers, they were still be able to breach the Chinese trap and rejoin the US 2nd Infantry Division.
The Marne Medal (French - "médaille de la Marne") was a French medal awarded to soldiers who had fought in the First Battle of the Marne, the Second Battle of the Marne or both engagements, particularly those who took part in fighting between 6 and 12 September 1914 on the Senlis front at Verdun.

Question: Which occurred first, the Battle of the Ch'ongch'on River or the Second Battle of the Marne?
Answer: Second Battle of the Marne