Question: What battle turned the tide for a theatre of war that the British 143rd Infantry Brigade saw active service in?
Context: The 143rd Infantry Brigade was an infantry brigade of the British Army that saw active service in both World War I and World War II.  In the First World War the brigade served on both Western Front and later the Italian Front.  During the Second World War the brigade fought in Belgium and France before being evacuated to England where it remained for the rest of the war and was finally disbanded in 1946.  Raised again in the 1980s, this brigade disbanded under Army 2020 in November 2014. The 156th (Scottish Rifles) Brigade was an infantry brigade formation of the British Army.  The brigade saw active service in both World War I and World War II with the 52nd (Lowland) Division. The 33rd Infantry Brigade was an infantry brigade of the British Army that saw active service in World War I and home service in World War II. The 155th (South Scottish) Brigade was an infantry brigade of the British Army that saw active service in both World War I and World War II.  Assigned to the 52nd (Lowland) Division, the brigade saw active service in the Middle East and on the Western Front during the First World War.  During the Second World War, now the 155th Infantry Brigade, it continued to serve with the 52nd Division in Operation Dynamo, and later in North-western Europe from late 1944 until May 1945. The Western Front was the main theatre of war during the First World War.  Following the outbreak of war in August 1914, the German Army opened the Western Front by invading Luxembourg and Belgium, then gaining military control of important industrial regions in France.  The tide of the advance was dramatically turned with the Battle of the Marne.  Following the Race to the Sea, both sides dug in along a meandering line of fortified trenches, stretching from the North Sea to the Swiss frontier with France, which changed little except during early 1917 and in 1918. The 199th (2/1st Manchester) Brigade was an infantry brigade formation of the British Army that saw active service during the Great War as part of 66th (2nd East Lancashire) Division and was reformed as 199th Infantry Brigade in World War II, serving with 55th (West Lancashire) Infantry Division until August 1944 when it was redesignated 166th Infantry Brigade. The 23rd Infantry Brigade was an infantry brigade of the British Army that saw active service in both World War I, mainly on the Western Front, and World War II.  In the Second World War the brigade saw active service in the Syria-Lebanon Campaign, the Western Desert Campaign and the Burma Campaign. The 146th Infantry Brigade was an infantry brigade formation of the British Army, part of the Territorial Force (Territorial Army from 1920) with the 49th (West Riding) Infantry Division.  The brigade saw active service during both World War I and World War II, and during the early part of the Cold War.  The brigade was active from 1908 until 1967 when it was finally disbanded. The 138th (Lincoln and Leicester) Brigade was an infantry brigade of the British Army that saw active service in World War I with the 46th (North Midland) Division.  The brigade again saw active service in World War II, with the 46th Infantry Division. The 163rd Infantry Brigade was an infantry brigade of the British Army that saw active service during the First World War in Gallipoli and the Middle Eastern Theatre as part of the 54th (East Anglian) Division.  In the Second World War the brigade remained in the United Kingdom until it was disbanded in late 1943.
Answer: Battle of the Marne