The once great realm of Mengwi arose with the weakening of Gelgel in east Bali around 1650. Descendants of a Javanese nobleman' opposed the Gelgel ruler and moved to the village of Kapal around 1700. A certain I Gusti Agung Anom then married the daughter of I Gusti Panji Sakti, the mighty ruler of north Bali. He moved to Blayu, near Mengwi, and soon began to expand his territory.

All rulers of Mengwi became engaged in bitter power struggles, not only with the lords and rulers of neighboring realms, but also with members of their own clan. At this time, access to the north coast (via Marga) and to East Java was of great importance, because these areas lay on the vital shipping routes to the Moluccan spice isles. To have access to the southern sea - as antepode of the north - was also convenient for religious reasons. The ashes of the royal dead could be scattered here and purificatory and agricultural rituals could be held on the beaches.

The first ruler of Mengwi made a pilgrimage to Majapahit, land of the Javanese ancestors and of the sacred Mt Semeru. The second ruler did so as well, accompanied by the king of Klungkung. Mengwi and Klungkung 11 dilled allies from this time onwards, the ruler of Klungkung being called raja while the ruler of Mengwi was his patih (first minister).

In the 18th century, Mengwi expanded to the mountainous north around volcanic Lake Bratan, and to the west and east. Even the southern peninsula came under Mengwi's sway. The rulers mobilized people to construct huge irrigation works and transformed the landscape into a vast rice field.

As the result of a power struggle, a branch of the family based in Munggu reigned sometime after 1740. Cokorda Munggu then founded a new center, Puri Gede, in the village of Mengwi. He also created a large state temple here, Pura Taman Ayun, and a sea temple, Pura Ulun Siwi, far to the south in Jimbaran.

Between 1740 and 1770, Mengwi thus became a replica of the divine Hindu cosmos. The ancestors and gods lived in the north atop Mt Pengelengan, and holy irrigation water descended from Lake Bratan in the rivers Sungi and Petan. In the south, the demonic forces of the sea were venerated at Ulun Siwi, while at the center of this axis in Pura Taman Ayun - the rulers themselves were venerated as gods on earth.

A new power struggle around 1780 greatly weakened Mengwi, resulting in a loss of the western and southern villages. From 1829 onwards, I Gusti Agung Nyoman Mayun tried to expand again into Marga. (now Tabanan) and Payangan (now Gianyar). These areas were very important since they had rich coffee plantations. Coffee became an important export in the second half of the 19th century, attracting Chinese merchants, and with them came opium. The new ruler also built new temples and created a new axis in his realm - from Pura Panataran Agung in Tiingan, near the coffee plantations in the northeast, to the coastal temple in Seseh in the southwest.

When in 1872 the third powerful ruler of Mengwi, I Gusti Agung Nyoman Mayun, died, the realm began to decay. There were plagues and crop failures, serious conflicts concerning irrigation systems and dams, and family intrigues. Moreover, Mengwi lost the support of Klungkung. In 1891 first Klungkung and then Badung, joined after a while by Tabanan and Bangli, defeated Mengwi. The profitable coffee enterprises, the opium trade and the rice fields were divided among the conquerors. The realm of Mengwi ceased to exist, though the palaces and temples remained.

The Dutch took control of south Bali after 1906 and the former realm was then divided for administrative purposes between the neighboring districts of Tabanan and Badung. However, the inhabitants still feel themselves to be "people from the realm of Mengwi."