Majapahit at its height under Gajah Mada and Hayam Wuruk

After the murder of King Jayanagara in 1328 the throne passed to Tribhuwana, a daughter of the founder Raden Wijaya, who ruled in the name of her mother Gayatri. Gajah Mada, a former commander of the palace guard, became chief minister (patih) of Majapahit in 1331 according to George Coedès, in 1334 or 1336 according to other accounts. The Pararaton, a chronicle of the 15th or 16th century, says that on taking office he swore not to ‘amukti palapa’ — to enjoy rest or pleasure, as the phrase is variously understood — until he had conquered ten lands — Gurun, Seram, Tanjungpura, Haru, Pahang, Dompo, Bali, Sunda, Palembang and Tumasik (Singapore). In 1343 a Javanese expedition destroyed the ruling house of Bali, beginning a deep Javanisation of the island.

In 1350 Tribhuwana's son Hayam Wuruk, born in 1334, became king under the name Rajasanagara, with Gajah Mada still chief minister. According to the Pararaton and the later Kidung Sunda (the Nagarakretagama is silent, and some historians doubt the story), in 1357 the king of Sunda in western Java brought his daughter to Majapahit to marry him; at Bubat, north of the capital, Gajah Mada insisted on treating her as a vassal princess brought in tribute, and the Sundanese king and his followers were killed in the fighting that followed. Gajah Mada died in 1364. The Nagarakretagama of 1365 lists as Majapahit's dependencies places in Sumatra, the Malay Peninsula, Borneo and eastern Indonesia as far as the coast of New Guinea, and names Siam with Ayutthaya, Champa, Cambodia and Đại Việt among friendly countries; between 1370 and 1381 Hayam Wuruk sent repeated embassies to the new Ming court.

How far this ‘empire’ really reached is debated. Coedès took the list as evidence that Majapahit's suzerainty covered almost all of what became the Dutch East Indies and much of the Malay Peninsula; other historians note that direct Javanese administration hardly extended beyond eastern Java and Bali, and that the distant ‘dependencies’ were tied to Majapahit mainly by trade. The reign was also an age of court culture: the temple of Panataran was completed, and the poet Tantular wrote the Sutasoma, from which Indonesia took its motto Bhinneka Tunggal Ika, ‘unity in diversity’. After Hayam Wuruk's death a succession war (1401–1406 according to Coedès, 1405–1406 according to others) hastened the kingdom's decline.