Question: The wormhoudt massacre occurred during a battle that brought land operations on the Western Front to an end until what date?

Context paragraphs:
Battle of France: The Battle of France, also known as the Fall of France, was the German invasion of France and the Low Countries during the Second World War.  In six weeks from 10 May 1940, German forces defeated Allied forces by mobile operations and conquered France, Belgium, Luxembourg and the Netherlands, bringing land operations on the Western Front to an end until 6 June 1944.  Italy entered the war on 10 June 1940 and attempted an invasion of France.

Wormhoudt massacre: The Wormhoudt massacre (or Wormhout massacre) was the mass murder of 80 British and French POWs by Waffen-SS soldiers from the 1st SS Division Leibstandarte SS Adolf Hitler during the Battle of France in May 1940.

Jedidiah Preble: Brigadier General Jedidiah Preble (born 1707, York Maine, d. 1784) was Captain of Infantry in Samuel Waldo’s Regiment, whom he brought land from and settled in Falmouth, Maine (present-day Portland, Maine).  He served in the Siege of Louisbourg (1745).  He also fought in the Battle of Grand Pre (1747).  He accompanied John Winslow on his expedition up the Kennebec River and participated with him the following year in the Battle of Fort Beauséjour (1755) where he was wounded.  He then participated in the Cape Sable Campaign.  After the British took control of the Saint John River, they took control of the final river the Penobscot.  Preble became commander at the newly built Fort Point (formally Fort Pownal) on the Penobscot River (1759).  He was also active in the American Revolution.

Vukovar massacre: The Vukovar massacre, also known as the Vukovar hospital massacre or the Ovčara massacre, was the killing of Croatian prisoners of war and civilians by Serb paramilitaries and the Yugoslav People's Army (JNA) at the Ovčara farm southeast of Vukovar on 20 November 1991, during the Croatian War of Independence.  The massacre occurred shortly after Vukovar's capture by the JNA, Croatian Serb Territorial Defence (TO), and paramilitaries from neighbouring Serbia.  It was the largest massacre of the war and the worst war crime in Europe since World War II up until that point.

Pauma massacre: The Pauma massacre occurred in December 1846, north of Escondido, California.  Luiseño Indians killed eleven Mexicans, Californio lancers who had stolen horses from them.  The action was related to a series of regional conflicts during the Mexican–American War and followed the Battle of San Pasqual in California.  Fundamentally, it was also related to the appropriation of Mission Luiseno land from the Luiseño after the successful mission with a population of 3,000 was secularized in 1833.  Gov. José Figueroa had granted the Luiseño three pueblos including Las Flores and San Pascual.  Pío Pico was to hold the mission land in trust for the government as administrator pending a decision on what to do with it.  Eventually, Pico took Las Flores as his personal ranch.  Pico was the man who led the Mexicans at the battle of San Pascual.  The Kumeyaay Indians lived at San Pascual, though the Kumeyaay were from the next mission, San Diego, they also viewed Pio Pico with distrust, and their sympathies for the Americans may have been decisive, given their knowledge of the terrain in which they lived.  The Mexicans lost and afterwards took 11 horses from a nearby Luiseño community, which then retaliated by killing 11 Mexican Californio soldiers at the Massacre of Pauma.

Nag Hammadi massacre: The Nag Hammadi massacre was a massacre of Coptic Christians carried out on the eve of 7 January 2010, in the Egyptian city of Nag Hammadi.  The massacre occurred at the hands of Muslim gunmen in front of the Nag Hammadi cathedral, as Coptic Christians were leaving the church after celebrating the midnight Christmas mass.  The massacre resulted in the murder of seven Copts and one Muslim bystander.  Nine other Copts were confirmed to be wounded, and two Muslims were reportedly wounded in the attack.

Bulhoek massacre: The Bulhoek massacre occurred on 24 May 1921, in the South African village of Bulhoek in the then Cape Province (today part of Eastern Cape).  After a dispute over land in Bulhoek, dating back to 1920, an 800-strong police force from the Union of South Africa and led by Colonel Johan Davey and General Koos van der Venter gathered at Ingxingwa Ye Nkunzini, in the Bulhoek valley, and Ingxingwa ka Stivini, Steven's Valley.  At the same time 500 men known as the "Israelites", armed with spears and knobkerries, and led by Enoch Mgijima, gathered in an open field, ready for battle.  After failed final negotiations between the two parties, a battled ensued.  The 20-minute battle, which left an estimated 163 Israelites dead, 129 wounded and 95 taken as prisoners, became known as the Bulhoek Massacre.

29th Army (Soviet Union): It was first formed in July 1941 in the Moscow Military District on the basis of 30th Rifle Corps.  The 245th, 252nd, 254th and 256th Rifle Divisions, and a number of smaller units made up the Army.  It joined the Front of reserve armies and conducted defensive works at Staraya Russa, Demyansk, Ostashkov, Selizharovo.  It was reassigned on July 21, 1941, to the Soviet Western Front, and with Western Front it took part in the Battle of Smolensk, conducted defensive fights in area to the south of the city of Toropets and on left I protect Volga on a site Rzhev, Staritsa.  As part of the Soviet Western Front, since October 17 of the Kalinin Front it participated in the defense of Kalinin, and the Kalinin, Rzhev–Vyazma 1942, and Rzhev–Sychyovka offensive operations (the Battles of Rzhev).  From the end of August 1942 the army defended occupied boundaries on the left bank of the Volga River.  In the beginning of February, 1943 the Army's units were transferred to 5th and 20th Armies, and the headquarters was reorganised as headquarters 1st Tank Army.

Phoney War: The Phoney War (French: "Drôle de guerre" ; German: "Sitzkrieg" ) was an eight-month period at the start of World War II, during which there were no major military land operations on the Western Front.  It began with the German invasion of Poland on 1 September 1939 and the declaration of war by the United Kingdom and France against Nazi Germany on none }} , and ended with the German attack on France and the Low Countries on 10 May 1940.

Anuradhapura massacre: The Anuradhapura massacre occurred in Sri Lanka in 1985 and was carried out by the Liberation Tigers of Tamil Eelam.  This was the largest massacre of Sinhalese civilians by the LTTE to date; it was also the first major operation carried out by the LTTE outside a Tamil majority area.  The responsibility for the massacre was not openly claimed by any Tamil militant group and some of the groups, including PLOTE and TULF, expressed revulsion at the attack.

Supporting paragraphs: Wormhoudt massacre Battle of France
Answer: 6 June 1944