Question: Did Operation Undertone or Operation Diadem take place first?

Context paragraphs:
1919–20 PCHA season: The 1919–20 PCHA season was the ninth season of the professional men's ice hockey Pacific Coast Hockey Association (PCHA) league.  Season play ran from December 26, 1919, until March 10, 1920.  The season was enlarged to 22 games per team.  The Seattle Metropolitans club would place first during the regular season and then won the play-off with Vancouver Millionaires to take the PCHA championship.  The Mets then played in the 1920 Stanley Cup Finals series against Ottawa Senators, National Hockey League (NHL) champions.  The Senators won the best-of-five series three games to two.

Operation Diadem order of battle: Operation Diadem order of battle is a listing of the significant formations that were involved in the fighting on the Winter Line and at the Anzio bridgehead south of Rome during "Operation Diadem" in May - June 1944 which resulted in the Allied breakthrough at Cassino and the breakout at Anzio leading to the capture of Rome.

1967 in the Vietnam War: Operation Deckhouse Five was conducted by the United States Marine Corps (USMC) and South Vietnamese Marine Corps forces along the Mekong River Delta.  The operation was notable in that it was a sizable, combined USMC and Vietnamese Marine amphibious operation and it was the last Special Landing Force (SLF) amphibious landing to take place beyond the boundaries of I Corps.  The operation occurred January 6–15, 1967.

Operation Bertram: Operation Bertram was a major Second World War deception operation practised by the allied forces in Egypt led by Bernard Montgomery in the months leading up to the Second Battle of El Alamein in 1942.  Bertram was devised by Dudley Clarke to deceive Erwin Rommel about the timing and location of the allied attack.  The operation consisted of physical deceptions using dummies and camouflage, designed and made by the British Middle East Command Camouflage Directorate led by Geoffrey Barkas.  These were accompanied by electromagnetic deceptions codenamed "Operation Canwell" using false radio traffic.  All of these were planned to make the enemy believe that the attack would take place to the south, far from the coast road and railway, and about two days later than the real attack.

Operation Mailfist: Operation Mailfist was a planned Allied offensive to liberate Singapore from Japanese occupation during World War II.  It was intended to follow on from the landing in Malaya, Operation Zipper, and take place between December 1945 and March 1946.  However, it was not conducted as Japan surrendered shortly before Operation Zipper was to have been launched.  Instead, Singapore was re-occupied in the unopposed Operation Tiderace.

Operation Diadem: Operation Diadem, also referred to as the Fourth Battle of Monte Cassino or, in Canada, the Battle of the Liri Valley, was an offensive operation undertaken by the Allies of World War II (U.S. Fifth Army and British Eighth Army in May 1944, as part of the Italian Campaign of World War II.  "Diadem" was supported by air attacks called Operation Strangle.  The opposing force was the German 10th Army.

Operation Undertone: Operation Undertone was a large assault by the U.S. Seventh and French 1st Armies of the U.S. Sixth Army Group as part of the Allied invasion of Germany in March 1945 during World War II.

Operation Mountain Fury: Operation Mountain Fury was a NATO-led operation begun on September 16, 2006 as a follow-up operation to Operation Medusa, to clear Taliban rebels from the eastern provinces of Afghanistan.  Another focus of the operation was to enable reconstruction projects such as schools, health-care facilities, and courthouses to take place in the targeted provinces.

Execution model: An execution model specifies how work takes place.  Every programming language has an execution model, which is specified as part of the language specification, and is implemented as part of the language implementation.  The details in the specification of an execution model cover things such as what is an indivisible unit of work, and what are the constraints on the order in which those units of work take place.  For example, the addition operation is an indivisible unit of work in many languages, and in sequential languages such units of work are constrained to take place one after the other.

Amory Adventure Award: The Amory Adventure Award is an award in the Canadian Venturer program.  Unlike all other awards and badges, for example the Queen's Venturer Award, the Amory Award is only granted to one Venturer company each year.  All Venturers who take part in an Amory Award expedition (whether or not they are members of the winning company) receive a participation badge to wear on the uniform.  The first-place company's name is recorded on the Amory Adventure Trophy, which the company may keep for nine months.  Companies that place first, second, and third each receive a trophy of their own to keep.

Supporting paragraphs: Operation Undertone Operation Diadem
Answer: Operation Diadem