Cham–Annamese War

The Cham-Đại Việt War of 1471 began when Emperor Lê Thánh Tông of Đại Việt launched a military expedition that is widely regarded as marking the downfall of Champa. The Đại Việt forces attacked and sacked the capital Vijaya, and decimated the Cham army. As a result of the conflict, Champa was forced to cede territory to Annam and from thereafter ceased to pose a threat to Annamese territory.

Invasion
The Chams' earlier attack on Angkor led the Khmers to ignore the Chams' request for assistance when Vietnam invaded.

The Cham feared an imminent Vietnamese attack, and requested that Ming China bring the Vietnamese back in line by force and clearly demarcate the border between Champa and Vietnam. China only verbally rebuked the Vietnamese for their invasions, which the Vietnamese ignored, proceeding to attack and destroy the Cham.

The Vietnamese then readied their forces for war. On November 28, 1470, Le Thanh Tong formally launched his attack as a 100,000-strong Vietnamese naval expedition set out that day, followed by another Vietnamese army consisting of 150,000 men on December 8.

The Vietnamese army was reorganized to copy the Chinese army, armed with gunpowder weapons. Le Thanh Tong raised a 300,000-strong army which outnumbered the 100,000-strong Cham army, although at a massive financial cost which drained the Vietnamese treasury of 1,000 gold liang each day.

Aftermath
The Vietnamese conducted a genocide campaign against the Cham, slaughtering 60,000 when taking the capital. The Vietnamese committed arson and theft and burned massive parts of Champa, seizing the entire country. The Cham told the Chinese that "Annam destroyed our country". The Chinese Ming Dynasty records record the Vietnamese destruction of Champa. The Vietnamese enslaved several thousand Cham and enacted forced assimilation of Vietnamese culture onto Chams. The Chams informed the Chinese that they continued to fight against the Vietnamese occupation of their land, which had been turned into the 13th province of Vietnam.

The Chinese government sent a censor, Ch'en Chun, to Champa in 1474 to install the Champa King, but he discovered Vietnamese soldiers had taken over Champa and were blocking his entry. He proceeded to Malacca instead and its ruler sent back tribute to China. Malacca sent envoys to China again in 1481 to inform the Chinese that while going back to Malacca in 1469 from a trip to China, the Vietnamese attacked them, castrating the young and enslaving them. The Malaccans reported that Vietnam was in control of Champa and also that the Vietnamese sought to conquer Malacca, but the Malaccans did not fight back due to lack of permission from the Chinese to engage in war. The Chinese Emperor scolded them, ordering the Malaccans to strike back with violent force if the Vietnamese attacked.

The Champa kingdom was destroyed by the invasion, leaving small rump states which lasted until 1832, when Vietnamese emperor Minh Mang initiated the final conquest of the remnants of Champa. Around 162,000 Cham remain in Vietnam today.

The trade in Vietnamese ceramics was damaged due to the plummet in trade by Cham merchants after the invasion.

The Chinese scholar 吳樸 Wu Pu recommended that to help stop the Vietnamese, China should help resuscitate the Champa Kingdom.