The Kathmandu court was practically paralysed by intrigue and assassinations during the first half of the nineteenth century, culminating in the ghastly Kot massacre of 1846, in which more than fifty courtiers were butchered in a courtyard off Kathmandu's Durbar Square. In the ensuing upheaval, a shrewd young general, Jang Bahadur , seized power, took the title Rana and proclaimed himself prime minister for life, an office which he later made hereditary by establishing a complicated roll of succession. Though the "Rana" title has generally been equated with that of a prime minister, technically it conferred a grade of kingship. The holder's full title was Shri Tin Maharaja (short for Shri Shri Shri Maharaja; "Shri" is an honorific prefix). The king's was, and still is, Shri Paanch (Five Shri) Maharajdhiraj. For the next century, the kings of Nepal were nothing more than puppets, while Ranas ruled like shoguns and packed the palace with their ever-increasing offspring. Authoritarian and blatantly exploitative, they built grandiose palaces while putting virtually no money into public works, suppressed education for fear it would awaken opposition, and remained firmly isolationist to avoid losing control to the British. (Ironically, an impoverished Nepal suited Britain, since it assured a steady supply of willing Gurkha cannon fodder.) Only a handful of foreign dignitaries were allowed to enter - usually only as far as Chitwan - and even the British resident wasn't allowed to venture beyond the Kathmandu Valley. To survey Nepal and Tibet, Britain had to send in Indian spies disguised as Buddhist monks.

Yet Jang Bahadur knew the value of staying on good terms with the British Raj, now at its zenith; in 1850 he broke with tradition and travelled to England, where he met Queen Victoria and by all accounts cut a dashing figure. He returned with several Western affectations, including a fondness for Neoclassical architecture and epaulettes; soon after, to his credit, he abolished the practice of sati.

Other Ranas continued in the same vein. Chandra Shamsher Rana , who came to power in 1901 by deposing his brother, is best known for building the thousand-roomed Singha Durbar and (belatedly) abolishing slavery. He also made some feeble attempts at modernization, including the construction of Nepal's first college, railway, hydroelectric plant and paved roads. By 1940, underground resistance against the regime was developing, and Juddha Shamsher Rana had four plotters executed; after the fall of the Ranas these men were declared martyrs and a monument south of Kathmandu's Tudikhel was erected in their honour.