Question: The 8th Cavalry Brigade served on a front that was the main theater of during during what war?

Context paragraphs:
8th (Lucknow) Cavalry Brigade: The Lucknow Cavalry Brigade was a cavalry brigade of the British Indian Army formed in 1911 as a result of the Kitchener Reforms.  It was mobilized as 8th (Lucknow) Cavalry Brigade at the outbreak of the First World War as part of the 1st Indian Cavalry Division and departed for France.  It served on the Western Front with the division until it was broken up in March 1918.

8th (Lucknow) Division: The 8th (Lucknow) Division was a formation of the British Indian Army's Northern Army that was first formed as a result of the Kitchener reforms of the Indian Army in 1903.  The Division remained in India on internal security duties during World War I, though the 8th (Lucknow) Cavalry Brigade was transferred to the 1st Indian Cavalry Division and served in France on the Western Front, and the 22nd Lucknow Infantry Brigade served as part of the 11th Indian Division in Egypt.

116th Cavalry Brigade Combat Team: The 116th Cavalry Brigade Combat Team is the largest formation of the Idaho Army National Guard.  It is headquartered at Gowen Field, Boise, Idaho.  It has been reorganized into a Heavy Brigade Combat Team (HBCT).  The 116th Cavalry Brigade Combat Team has units located throughout Idaho, Montana, Oregon, and Nevada.  It was reorganized into a heavy armor brigade in 1989.  Often referred to as the Snake River Brigade and formerly known as the 116th Armored Cavalry Regiment, the unit includes about 3,000 citizen-soldiers from Idaho.

4th (Secunderabad) Cavalry Brigade: The 4th (Secunderabad) Cavalry Brigade was a cavalry brigade of the British Indian Army that formed part of the Indian Army during the First World War.  It was formed as Secunderabad Cavalry Brigade in February 1915 to replace the original brigade that had been mobilized as the 9th (Secunderabad) Cavalry Brigade for service on the Western Front.  It remained in India throughout the war.

4th Cavalry Regiment (United States): The 4th Cavalry Regiment is a United States Army cavalry regiment, whose lineage is traced back to the mid-19th century.  It was one of the most effective units of the Army against American Indians on the Texas frontier.  Today, the regiment exists as separate squadrons within the U.S. Army.  The 1st Squadron of the 4th Cavalry's official nickname is "Quarterhorse", which alludes to its 1/4 Cav designation.  The 3rd Squadron of the 4th Cavalry's official nickname is "Raiders".  Today, the "1st Squadron, 4th Cavalry", "2nd Squadron, 4th Cavalry", "4th Squadron, 4th Cavalry", and "6th Squadron, 4th Cavalry" are parts of the 1st Infantry Division, while the "3rd Squadron, 4th Cavalry" serves as part of the 25th Infantry Division.  On 23 September 2009, the "4th Squadron, 4th Cavalry" officially stood up at Fort Riley, Kansas as part of the 1st "Devil" Brigade, 1st Infantry Division.  On 28 March 2008, the "5th Squadron, 4th Cavalry" officially stood up at Fort Riley, Kansas as part of the 2nd "Dagger" Brigade, 1st Infantry Division.  The 6th Squadron, 4th Cavalry served as part of the recently inactivated 1st Infantry Division, 3rd "Duke" Brigade, at Fort Knox, Kentucky.

Western Front (World War I): 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.

3rd (Meerut) Cavalry Brigade: The 4th (Meerut) Cavalry Brigade was a cavalry brigade of the British Indian Army that formed part of the Indian Army during the First World War.  It was formed as 14th (Meerut) Cavalry Brigade in November 1914 to replace the original Meerut Cavalry Brigade that had been mobilized as the 7th (Meerut) Cavalry Brigade for service on the Western Front.  It remained in India throughout the war, before taking part in the Third Anglo-Afghan War in 1919.

316th Cavalry Brigade: The 316th Cavalry Brigade of the United States Army is the brigade responsible for the training of U.S. Army Cavalry and Armor officers and non-commissioned officers.  The 16th Cavalry Regiment was redesignated as this unit in July 2010.  The 316th Cavalry Brigade is currently assigned to Fort Benning, Georgia, in accordance with the Base Realignment and Closure of 2005.

2nd Squadron, 16th Cavalry Regiment: The 2nd Squadron, 16th Cavalry Regiment (2-16 CAV) is the United States Army Armor School's proponent for Armor Basic Officer Leaders Course (ABOLC).  The squadron's four troops are Hawk Troop, Ironhorse Troop, Killer Troop, and Darkhorse Troop.  The Headquarters and Headquarters Troop (HHT) is responsible for training lieutenants awaiting their ABOLC class or who have completed the course and are awaiting for follow-on orders or to attend functional schools.  HHT is also responsible for the certification of all instructors at the Armor Basic Officer Leadership Course.  Each instructor is initially certified in the U.S. Army Basic Instructor Course, and then must undergo specific instruction to learn the doctrine that is taught to the Armor and Cavalry lieutenants.  ABOLC is the introductory skills course for United States Army Cavalry and Armor second and first lieutenants.  These officers, recent graduates of the United States Military Academy, ROTC programs, and Officer Candidate School, receive eighteen weeks of training in basic soldiering skills, maneuver tactics, troop- and company-level strategy, and logistical planning.  ABOLC consists of three phases - the first focusing on individual soldier skills; Phase II focusing on platform and crew training; and Phase III focusing on tactics and field training.  The final exercise, the Competitive Maneuver Exercise (CME), is a strenuous seven-day problem-solving exercise which evaluates a students ability to demonstrate proficiency in cumulative course outcomes.  Students are evaluated based on their performance during each exercises, and rotate among every position within a platoon and troop.  The course is taught by officers, non-commissioned officers, and civilians from the 2nd Squadron, 16th Cavalry Regiment of the 199th Infantry Brigade.  The 2nd Squadron, 16th Cavalry currently operates out of Harmony Church in Fort Benning, Georgia.  The squadron was reassigned from the 316th Cavalry Brigade in the fall of 2013 as part of restructuring within the Maneuver Center of Excellence.

8th Cavalry Brigade (United Kingdom): The 8th Cavalry Brigade was a cavalry brigade of the British Army in World War I.  It was formed in Belgium in 1914 and served on the Western Front as part of the 3rd Cavalry Division.  It left the 3rd Cavalry Division on 14 March 1918.

Supporting paragraphs: 8th Cavalry Brigade (United Kingdom) Western Front (World War I)
Answer: the First World War