Rise of King Mawrong

After a brief period, King Mawrong Hang came to prominence and took over Terai lands of Chethar, Bodhey, Panthar and Ilam (present day Jhapa, Morang Sunsari and Dhankuta). He named his Kingdom Morang after his name and rose to power. He subdued all the Ten Limbu Kings of Limbuwan and became their overlord. He died with out any male heir and King Uba Hang took over as supreme ruler of Limbuwan in 849 AD- 865 AD. He made many religious and social reforms in Limbuwan. Uba Hang's worthy son Mabo Hang succeeded him in 865 AD and ruled till 880 AD. Uba hang kept on with the reforms his father had started. Uba Hang was succeeded by his son Muda Hang. Muda Hang was a weak ruler so the local chiefs started ruling their areas independently. Muda Hang was succeeded by his son Wedo Hang, by this time Limbuwan was in chaos and every principality was ruling independently and fighting with each other. Wedo hang was murdered and his son Chemjonghang succeeded.

Rise of King Sirijonga

During this chaos and the waning phase of King Chemjong hang, King Sirijonga of Yangwarok kingdom rose to power. He subdued all the independent rulers and took over as the new supreme ruler of Limbuwan. He built two big forts in Phedap (present day Terhathum district) and Chainpur (present day Sankhuwasabha district). The remains of the structure still stand today. One of legacy was that he brought all the Limbus under the same writing system in Kirat script. He also brought feudal reform in Limbuwan and divided Limbuwan into new boundaries and districts.
Eventually after the establishment of Namgyal dynasty in Sikkim and under the Lho-Mehn-Tsong Tsum, a treaty between the Bhutia, Lepcha and Limbu people of the Sikkim area, Limbuwan lost the area between Kunchenjunga range (present day eastern border of Nepal) and Teesta River to the Bhutia Kings of Sikkim. Since then Limbuwan comprises all the area between Arun River and Koshi River in the west to Kunchenjunga Mountains and Mechi River in the east.
In the beginning of 15th century, the descendants of King Sirijonga became weak and Limbuwan again fell into chaos and anarchy. At the time Lowland Limbuwan Kingdom of Morang was ruled by King Sangla Ing. Sangla Ing declared independence and became the first independent ruler of Morang in a century. His son Pungla Ing adopted Hinduism and changed his name into Aamar Raya Ing. He was succeeded by his descendents, who also bore Hindu names. Kirti Narayan Raya Ing, Aap Narayan Raya Ing, Jarai Narayan Raya Ing, Ding Narayan Raya Ing, and Bijay Narayan Raya Ing.
King Bijay Narayan Raya Sanlga Ing built a new town in the middle of Varatappa and Shangori fort and named it Bijaypur after him. He had no issue and died without an heir.
Bijaypur town was founded in 1584 AD and is currently located next to Dharan, Sunsari District. Bijaypur town remained the capital of Morang Kingdom and Limbuwan region until the Gorkha Limbuwan War in 1774 AD.
Morang Kingdom was the most powerful and influential of all the Kingdoms in Limbuwan region and was able to establish its hegemony among all the other Limbu rulers. But in 1609 AD Kirant King Lo hang Sen of Sen dynasty captured Morang and ruled it for seven generations.
King of Phedap Murray Hang was made the chief minister of Morong. He stayed in Bijaypur and the King of Morong made his post hereditary. Murray Hang was given a Hindu name and he became Bidya Chandra Raya . His descendents remained Chief Ministers of Morong until Buddhi Karna Raya . Buddhi Karna Raya succeeded the last Sen King of Morang Kama Datta sen and sat in the throne of Bijaypur Palace in 1769 AD