グルカ戦争
Bhimsen Thapa ruled for 31 years as Mukhtiyar and implemented large number of reforms in agriculture, forestry, trade and commerce, judiciary, military, communications, transportations, slavery, human trafficking and other social evils in his premiership. During Bhimsen Thapa's prime ministership, the Gurkha Empire had reached its greatest expanse from Sutlej river in the west to the Teesta river in the east. However, Nepal entered into a disastrous Anglo-Nepalese War with the East India Company lasting from 1814–16, which was concluded with the Treaty of Sugauli, by which Nepal lost almost one-third of its land. It also led to the establishment of a permanent British Residency. The death of King Girvan Yuddha Bikram Shah in 1816 before his maturity, and the immature age of his heir, King Rajendra Bikram Shah, coupled with the support from Queen Tripurasundari (the junior queen of Rana Bahadur Shah), allowed him to continue to remain in power even after Nepal's defeat in the Anglo-Nepalese War.