Champa–Đại Việt War (1367–1390)

Trần Dụ Tông was an incompetent and impotent ruler that he had no heir to succeed.[18] He picked his brother's son Dương Nhật Lễ as the successor, although Nhật Lễ did not come from the royal family. In 1370, the Trần family launched a bloody coup that dethroned Dương Nhật Lễ. Prince Trần Phủ was crowned as Trần Nghệ Tông (r. 1370–1372). Nhật Lễ's Queen mother, however, fled to Champa and urged Chế Bồng Nga to attack the Trần for her revenge.[19]

Chế Bồng Nga then massed a large fleet, heading north. 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. All Vietnamese books held in the royal palace were lost.[20]

Cham empire at its peak during the reign of Che Bong Nga in 1380s

Cánh Tiên temple near Vijaya Citadel

In 1372 Trần Nghệ Tông crowned his younger brother Trần Kính as king Trần Duệ Tông (junior king) while himself served as the senior king. 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.[21] In 1372 Chế Bồng Nga sent a letter to the Hongwu Emperor of China warned that the Viets were about to attack his country, demanded China for protection and war materials.[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. 1324–1381).[23]

According to the Toàn thư, in 1376, Chế Bồng Nga launched incursions into Hoá Châu (Thừa Thiên Huế). 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. Hồ Quý Ly was responsible for transporting supplies and army from Nghệ An, Tân Bình and Thuận Hoá, while general Đỗ Tử Bình commanded the army. In early 1377, Champa initially tried to negotiate, but corruption in Vietnamese military leadership thwarted this effort. Trần Duệ Tông continued to march his army to Champa's capital Vijaya [note 6]. Duệ Tông saw a deserted encampment, where one of Duệ Tông's officers had informed him that it could be a trap of Chế Bồng Nga. Duệ Tông ignored the officer and continued to advance forward into the Vijaya citadel, where Chế Bồng Nga and his army ambushed the Viet army. Southerners in the Viet army turned and defected to the Cham.[21] Duệ Tông's army was smashed into an undisciplined mob while he and three generals were slain during the chaos.[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."[27]

Đỗ Tử Bình abandoned the position and fled north for his life.[28] The Chams captured Trần Húc, a Vietnamese prince. Chế Bồng Nga married off his daughter to Húc, and put the Prince in charge of a Cham army attack into Nghệ An.[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.[21][30] In early 1378 the pro-Cham Prince Trần Húc appeared in Nghệ An, claiming to be king of Đại Việt. He and Chế Bồng Nga rallied with people from southern provinces under Cham occupation, together with Cham force overran Đỗ Tử Bình, besieged and took Hanoi for the third time, pillaged the city.[31] They forced the king Trần Phế Đế to move royal treasures to Mount Thienkien and the Kha-lang Caves[note 7] in 1379.[32] After the Cham retreated back to Thanh Hoá, Hồ Quý Ly reappeared on the frontline. 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. Royal family owning lands were distributed equally per peasant to maximize the war effort, still the Viet resources were almost exhausted.[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. The Cham retreated back to Quảng Bình, while Quý Ly's force regained Nghệ An and executed a local leader who sided with the Cham. 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.[31] In early 1383 Hồ Quý Ly dispatched off a naval fleet advancing into Cham occupying territories, but was stopped by a storm.

In summer of that year, Chế Bồng Nga launched a new northward offensive. 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. The Cham army approached Sơn Tây, west of the Viet capital Hanoi. Trần Nghệ Tông sent a general who tried to hold off the Cham advance, but was defeated. Road to Hanoi laid open. 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.[33][34][35]

The crisis and survival period of the late 14th century Đại Việt is proven deadly. War with Champa, internal rebellions, famines triggered by the war itself, democide, climate changes and disease, together combined decreased the Vietnamese population about 25% of total population (roughly 800,000 deaths, estimated by Yumio Sakurai based on excavation study on 14th century Red River Delta).[42] With gunpowder, the Vietnamese had saved their state from the brink of dismantling. The Cham sacks of Hanoi also demoralized Dai Viet's aristocracy and Confucians, giving space to a new Confucian literati class, rivaling traditional Buddhist culture and aristocratic governance, which would dominate the Vietnamese court in the next century under the patron of Lê Thánh Tông.[43] Hồ Quý Ly now was the most powerful figure in Đại Việt after the war. As the chief minister, he conducted a series of reforms without the king's approval, despite the country was in recovery from destruction. 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 January 1395 Nghệ Tông died. In 1398 Quý Ly manipulated king Trần Thuận Tông into abdicating, installed two-year-old Prince An as Trần Thiếu Đế (r. 1398–1400). 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.[44][45]

In Champa, king Jaya Simhavarman VI abandoned most of his previous ruler's conquered lands. Champa gradually declined. Simhavarman V also failed to have recognition from the Ming. The Ming Emperor viewed La Khai as the usurper who assassinated Chế Bồng Nga, and refused to receive his tribute, along with Vietnamese tribute.[46][47] La Khai was succeeded by his son Indravarman VI (r. 1400–1441), who would confront Hồ Quý Ly in the next brief border war.

Mainland Southeast Asia in 1410s as Dai Viet was conquered by the Ming dynasty in 1407

In 1401 Hồ Quý Ly raised his second son Hồ Hán Thương (r.1401–1407) who has Trần bloodline as king and he became the senior king. 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.[48]

According to the Toàn thư, in a desire to "attack Champa and conquer all the land south to the border of Siam," Hán Thương provoked a new war with Champa in 1403. 200,000 troops, an obvious exaggerated and controversial number, led by Hán Thương laid an unsuccessful siege of Vijaya which lasted for nine months. In contrast, the Ming Shilu does not record a war in 1403 between Champa and Annam.[49]

In 1403 Hán Thương sent an embassy to China. The Yongle Emperor demanded him to stop raiding Champa. In 1404 Hán Thương again raided Champa, prompting the Ming empire for action.[49] A 1405 memorial from Champa king Indravarman VI attached in the Ming Shilu claimed that Hán Thương raided his country in mid-1404, occupying a place called Sa Ly Nha (沙離牙) and seizing the king's (Ming) ceremonial costume; the Ming demanded that Đại Việt ceasing hostility against Champa. For the entry of 1406, the Ming accused the Hồ for invading Jiuzhou (Amaravati) and raiding Ban-da-lang, stealing 100 elephants from Champa, which were used by the Hồ to attack Zhan-sha and Li-ya, apparently two states bordering Champa.[49]

In 1406, in the banner of restoring the Trần dynasty, 215,000 Chinese troops ordered by Yongle invaded Dai Viet, arrested the Hồ kings, their family and turned Dai Viet kingdom into the empire's thirteenth province.[50] Four former territories gained by Hồ Hán Thương were returned to Champa.[51] Champa was visited by Zheng He's fleet several times.[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. He established a good relation with Indravarman VI, both sent embassies and presents to each other.[53] Lê Lợi's fourth grandson, the great king Lê Thánh Tông, however waged a war that decimated Champa in 1471.[54]

Chế Bồng Nga is remembered as the greatest hero of the Cham people and in Cham folklore. In Ede and Jrai language, he is memorialised as R'čăm B'nga (Anak Orang Cham Bunga, lit. The bright flower of the Cham people). During its peak, Chế Bồng Nga's empire could have extended from the Red River Delta to southeastern Laos, to former territories controlled by the Khmer Empire in south.[55]

Cham influence can also be detected in stone pedestals found in various pagodas on both sides of the Red River. The pedestals have been dated to the second half of the fourteenth century; many bear dates from 1364 to 1394, the period of the Chế Bồng Nga's campaign against the Viets.[56]