Maharaja Jung Bahadur Kunwar Ranaji, GCB, GCSI was a Khas Rajput ruler of Nepal and founder of the Rana Regime in Nepal. Jung Bahadur took control of the government after killing an alleged usurper, Gagan Singh, who was accused of plotting with the junior queen in 1846 to become prime minister by putting the queen's son on the throne. His original name was Bir Narsingh Kunwar but he was popularly known as Jang Bahadur, a name given to him by his maternal uncle Mathabar Singh Thapa. Mathabar Singh Thapa used to call Jang Bahadur Jangay for his boldness.
His mother Ganesh Kumari was the daughter of Kaji Nain Singh Thapa, brother of Mukhtiyar Bhimsen Thapa of the then prominent ruling Thapa dynasty. During his lifetime, he eliminated the factional fighting at the court, removed his family's rivals like Pandes and Basnyats, introduced some innovations in bureaucracy and judiciary, and made efforts to modernize Nepal. He is one of the most important figures in Nepalese history. Some modern historians blame Jung Bahadur for setting up an oppressive dictatorship in Nepal that lasted 104 years- the dark period of Nepalese history.