In 1369, the crown of Đại Việt went to Dương Nhật Lễ, a man not from the Trần dynasty, which then triggered a short and deadly succession war in the capital.

In 1371 he led a fleet through the Gulf of Tonkin assaulted into the Viet capital Thăng Long (now Hanoi) and sacked the city, and repeated three more times in 1378 and 1383.

In 1377 he killed emperor Trần Duệ Tông (r. 1373–1377) at the Battle of Vijaya, and rapidly extended his Champa Empire into the Red River Delta, threatening Đại Việt's existence and its ruling dynasty.

It was also the first time in Indochina gunpowder weapons and lethal firearms from Ming China were introduced into warfare, which determined the decisive victory for the Vietnamese force over Cham force in the battle of Luộc River where Chế Bồng Nga was killed in 1390 by firearms of Vietnamese Prince Trần Khát Chân that effectively stopped the Cham advance.

In 1306, Đại Việt retired emperor Trần Nhân Tông (r. 1278–1293) married off his daughter, Princess Huyen Tran (Queen Paramecvari), to king Chế Mân[note 1] (r. 1288–1307) of Champa as a confirmation of their alliance.

According to the Toàn Thư, in 1352 the Dai viet organized a naval assault on Champa, marching to Cổ Lũy (Quảng Ngãi), but failed when the Cham navy prevented them to link up with the supplies and were forced to turned back.

In 1361, Champa raided Đại Việt's southern coast, plundering the Huế areas, its surrounding highlands and kidnapped local youth who gathered during holiday.

Chế Bồng Nga quickly placed his kingdom in the favor of the new Hongwu Emperor as he dispatched the first embassy and sent tribute to the Ming court.

[15][16] Champa for a long time perhaps had a well-established connection with the Muslim trade and the Maritime Southeast Asian world, although the Majapahit considered the Vietnamese polity "highly respected as a very close ally.

The fleet sailed across the Gulf of Tonkin and struck southern Red River Delta in Spring 1371 while the Vietnamese had no organized army left in defense.

Cham force sacked the Viet capital of Thăng Long[note 5], set the city on fire, seized women, jewels, and silks.

The Viet court then spent time to refortifying the ties with its southern mandalas of Thanh-Nghệ and securing the capital as reaction to the rising Champa of Chế Bồng Nga.

[22] In 1375 Hồ Quý Ly (c. 1335–1408), a leader from Thanh-Nghệ, through beneficial royal contacts of his relatives, received a high military rank of the army, became the prominent figure of Đại Việt late 14th-century along with his rival Đỗ Tử Bình (c.

King Trần Duệ Tông assembled a massive army of 120,000 men with support from Nghệ An, Quảng Bình and Thuận Hoá, ready for a counterattack.

[24][25][26] The Ming Shilu and later Jesuit histories also report a Trần king named Chen Tuan (陳煓) died in Champa in 1377 "after engaging in a major war.

[29] Following the death of the Viet king, Chế Bồng Nga's mighty Chams pursued the disarrayed Viet troops forward north, rapidly advanced into the Red River Delta, met little resistance, and sacked Hanoi in late 1377, gaining control of vast territories including Thanh Hoá and Nghệ An, marked the apex of the Cham Empire.

To refill the empty treasure that was needed to train, equip, and supply soldiers, Quý Ly and a group of men increased the taxes per household and military manpower.

[31] The Cham resumed raiding to Thanh Hoá in 1380, but was fend off by joint force of Hồ Quý Ly and Đỗ Tử Bình.

In 1382 they pushed an assault on Thanh Hoá by both land and sea, but was repulsed by Nguyễn Đa Phương (?–1389), a local general and a protégé of Quý Ly.

Advised by general La Khai, this time he chose the western route through mountains of eastern Laos and Thanh Hoá, bypassing Hồ Quý Ly's army.

Nghệ Tông fled to the north of the Red River and sought asylum at Bao Hoa Palace, while Chế Bồng Nga's soldiers once again ransacked Đại Việt's capital, occupying it for six months before their departure.

Chế Bồng Nga together with Nguyên Diệu, a prince who defected to the Cham, led a hundred warships advanced into Thanh Hoá, attempted to get rid of Đại Việt once and forever.

Quý Ly also had support from the old king Trần Nghệ Tông who trusted him to plant his reforms and gained control over the royal family.

In 1400 he deposed Thiếu Đế and proclaimed himself ruler, establishing his clan in royal positions, murdered Thuận Tông and suppressed the Trần aristocracy, dissents and families who allied with them.

Quý Ly immediately mobilized an army of 15,000 men to invade Champa in Amaravati[note 9], but was forced to turn back due to floods.

[48] In 1402 Hồ Hán Thương and some former Cham generals launched several incursions into Amaravati, forcing Indravarman VI to ceded four regions Thăng, Hoa, Tư, and Nghĩa and Tân Ninh highlands to the Dai Ngu.

200,000 troops, an obvious exaggerated and controversial number, led by Hán Thương laid an unsuccessful siege of Vijaya which lasted for nine months.

[52] From 1418 to 1427 Vietnamese leader Lê Lợi launched a war of Independence that eventually drove the Chinese out of northern Vietnam and became king of restored Dai Viet in 1428.