The history of Nepal began with the arrival of the Kiratis in the Kathmandu Valley in the 7th and 8th Centuries. The Kirats ruled the Valley for 1225 years with 28 kings leading the kingdom over that period. Nepal became a political region which was united by kings or rulers of different kingdoms.

One of the kings who played a critical role in the unification of Nepal was Prithvi Narayan Shah who ascended to the throne of Gorkha kingdom in 1743. His political ambitions saw him unite smaller kingdoms.

The Kingdom of Nepal was founded in 1768-69 by King Prithvi Narayan Shah, who hailed from the Gorkha Kingdom. He envisaged a Himalayan Kingdom from Nepal to Kashmir.

Gorkhas conquered all of eastern Nepal by 1773. In 1777 they broke non aggression treaty with Sikkim and annexed Western portions of Sikkim. In September 1792, Chinese threw out of Tibet. Nepal refrained from making any efforts to extend territory to east and they march toward Himachal Hills.
Before the end of 18th century they had extended their dominion from Ganga to the Satluj, over the whole of Kumaon, Garhwal, Sirmaur and the Shimla Hill States.
Raja Karam Parkash (1793-1814) was succeeded to Sirmaur Gaddi, he was inexperienced ruler. Raja Ram Saran Singh of Hindur started interference in internal affairs of Sirmaur.

Two officers Ajit singh and Krishan singh conspired with Raja’s brother kanwar Ratan singh to occupy the throne. They besieged the Raja in Kangra, a fort in Sirmaur.

In a fight between Raja and his bother Cholu mian who resembled karma Prakash in appearance was killed and rumour was spread that the raja had been killed. Taking advantage of this confusion raja managed to escape and sought help from Gurkhas to regain throne from his brothers.
Amar Singh Thapa sent army under Bakti Thapa but they were forced to withdraw by
Hindur’s ruler at Jamata. In 1804 Gurkhas made another attempt Amar Singh Thapa came himself and expelled Kanwar Rattan Singh but throne was not handed over to Raja Karam Prakesh Amar Singh Thapa set up his own government
During this period Raja Ram Saran of Hindur win over the loyalties of Bara Thakurais. After sometime Raja Ram Saran of Hindur allied himself with Raja Sansar chand of Kangra who attacked Raja Mahan Singh of kahlur. He also built a fort at Dhar Jhanjiar.
Along with Raja Mahan Singh other hill chiefs were afraid of Sansar chand and they invited Amar Shingh Thapa who arrived by 1804 in Shimla Hill States. They defeated Hindur troops at Ajamgarh. In 1806 Kangra forced were defeated by Gurkhas at Mahal Morian (Hamirpur).
Raja Sansar Chand first took position at Tira Sujanpur and then took refuge in kangra fort. Struggle had continued for four years, as a last hope Raja Sansar chand in 1809 AD appealed to Maharaja Ranjeet Singh for help. This request was accepted after a month long negotiation in Jwalamukhi temple. Treaty was signed on 20th July A.D. 1809.
Sikh army defeated Gurkhas but forced Sansar chand to hand over Nagarkot fort on 24 august 1809 to Maharaja Ranjit Singh.
Desa Singh Majithia was appointed Nazim of the fort. After 1809 defeat Amar Singh Thapa established himself at Arki in small state of Baghal whose chief Jagat Singh was driven into exile in Palasi.
A force under Ranzor Singh Attack Sirmaur ruler Karam Prakash, forced him to leave
his state. He fled to Subathu and then to Buria in Ambala.
Thus Nahan and Jaythak (sirmaur) became important Gurkhas posts. Gurkhas built the Jagatgarh fortress in Shimla hill.

By the year 1810 Gurkhas succeeded to conquer Hindur, Jubbal, Pinder and Dhami. The fort of Nagana in Balsan state was also captured.
Bushar Raja Ugar Sen tried his level best to control Gurkhas but his death ease the
operation of Gurkhas.

Mohinder Singh next successor was minor who escaped with Wazir and Rajmata into the dense forest. Amar Singh Thapa left the state in 1812 and allowed the king to rule north of Sarahan mountain and beyond the Satluj for a payment of 12,000 per annum.

Now areas between Yamuna and Satluj had come under Gurkhas control. The Gurkha General Amar Singh Thapa remained in Rampur until 1813 A.D.