The Huế Massacre (Vietnamese: "Thảm sát tại Huế Tết Mậu Thân" , or "Thảm sát Tết Mậu Thân ở Huế, "lit.
 translation: "Tet Offensive Massacre in Huế") is the name given to the summary executions and mass killings perpetrated by the Viet Cong (VC) and People's Army of Vietnam (PAVN) during their capture, occupation and later withdrawal from the city of Huế during the Tet Offensive, considered one of the longest and bloodiest battles of the Vietnam War.
The Tet Offensive (Vietnamese: "Sự kiện Tết Mậu Thân 1968" , or "Tổng tiến công và nổi dậy Tết Mậu Thân") was one of the largest military campaigns of the Vietnam War, launched on January 30, 1968, by forces of the Viet Cong and North Vietnamese People's Army of Vietnam against the forces of the South Vietnamese Army of the Republic of Vietnam, the United States Armed Forces, and their allies.
 It was a campaign of surprise attacks against military and civilian command and control centers throughout South Vietnam.
 The name of the offensive comes from the Tết holiday, the Vietnamese New Year, when the first major attacks took place.
Tet 1969 refers to the attacks mounted by principally forces of North Vietnam and Viet Cong in February 1969 in South Vietnam during the Vietnam War, one year after the original Tet Offensive.
The Battle of Leyte Gulf is generally considered to be the largest naval battle of World War II and, by some criteria, possibly the largest naval battle in history.
Tet 1969 refers to the attacks mounted by principally North Vietnamese forces in February 1969 in South Vietnam during the Vietnam War, one year after the original Tet Offensive.
The Battle of Coral–Balmoral (12 May – 6 June 1968) was a series of actions fought during the Vietnam War between the 1st Australian Task Force (1 ATF) and the North Vietnamese 7th Division and Viet Cong Main Force units, 40 km north-east of Saigon.
 Following the defeat of the communist Tet offensive in January and February, in late April two Australian infantry battalions—the 1st and 3rd Battalions of the Royal Australian Regiment (RAR)—with supporting arms, were again deployed from their base at Nui Dat in Phuoc Tuy Province to positions astride infiltration routes leading to Saigon to interdict renewed movement against the capital.
 Part of the wider allied Operation Toan Thang I, it was launched in response to intelligence reports of another impending communist offensive, yet the Australians experienced little fighting during this period.
 Meanwhile, the Viet Cong successfully penetrated the capital on 5 May, plunging Saigon into chaos during the May Offensive in an attempt to influence the upcoming Paris peace talks scheduled to begin on the 13th.
 During three days of intense fighting the attacks were repelled by US and South Vietnamese forces, and although another attack was launched by the Viet Cong several days later, the offensive was again defeated with significant losses on both sides, causing extensive damage to Saigon and many civilian casualties.
 By 12 May the fighting was over, and the North Vietnamese and Viet Cong were forced to withdraw having suffered heavy casualties.
 US casualties were also heavy and it proved to be their most costly week of the war.
The Battle of Kham Duc was a major battle of the Vietnam War (also known, in Vietnam, as the "American War").
 The event occurred in Khâm Đức, now district capital of Phước Sơn District, then in Quảng Tín Province (now part of Quảng Nam Province, South Vietnam), on 10–12 May 1968.
 During the Tet Offensive of 1968, the Vietnam People's Army (PAVN) 2nd Division tried to capture Đà Nẵng but their attacks were quickly blunted by elements of the U.S. 1st Marine Division, the Americal Division, and the Korean Brigade that were guarding the city.
 North Vietnamese General Chu Huy Mân decided to disengage from the fight in the outskirts of the city, and pull the 2nd Division into the mountains where they could rest, rebuild, and prepare for the next major operation.
 Khâm Đức, a small district in the north of Quảng Tín, was chosen as the next target for the PAVN 2nd Division.
 Following the defeat of the North Vietnamese in Đà Nẵng, U.S. military intelligence agencies in I Corps Tactical Zone were confused by the movements of the North Vietnamese 2nd Division, because they could not track down the mysterious enemy unit.
During the early morning hours of 1 May, communist units initiated PHASE II of the Tet Offensive of 1968 (also known as the May Offensive, "Little Tet", and "Mini-Tet") by striking 119 targets throughout South Vietnam, including Saigon.
 This time, however, allied intelligence was better prepared, removing the element of surprise.
 Most of the communist forces were intercepted by allied screening elements before they reached their targets.
 13 NLF battalions, however, managed to slip through the cordon and once again plunged Saigon into chaos.
 Severe fighting occurred at Phú Lâm (where it took two days to root out the 267th NLF Local Force Battalion), around the Y-Bridge in Saigon, and at Tan Son Nhut Air Base.
 By 12 May the offensive was over as NLF forces withdrew from the area leaving behind over 3,000 dead and 7,500 wounded.
Leyte Gulf is a gulf in the Eastern Visayan region in the Philippines.
 The bay is part of the Philippine Sea of the Pacific Ocean, and is bounded by two islands; Samar in the north and Leyte in the west.
 On the south of the bay is Mindanao Island, separated from Leyte by the Surigao Strait.
 Dinagat Island partly encloses the gulf to the southeast, and the small Homonhon Island and Suluan Island, sit astride the eastern entrance to the Gulf.
 It is approximately 130 km (80 mi) north-south, and 60 km (40 mi) east-west.
USS "Leyte Gulf" (CG-55) is a "Ticonderoga"-class guided missile cruiser in the United States Navy.
 She was named in memory of the World War II Battle of Leyte Gulf in the Pacific.
 She is powered by four large gas-turbine engines, and she has a large complement of guided missiles for air defense, attack of surface targets at sea and ashore, and anti-submarine warfare (ASW).
 In addition, she carries two "Seahawk" LAMPS multi-purpose helicopters, whose primary mission is ASW.

Question: Which occurred first, the Battle of Leyte Gulf or Tet Offensive?
Answer: Battle of Leyte Gulf