Koirala went back to India, and began looking for arms to storm Kathmandu. Finally, Koirala led the Revolution of 1951, which overthrew Nepal's 104-year-old Rana regime. The last Rana prime minister was dismissed in October 1951 when the Rana-Congress coalition cabinet (in which Koirala served for nine months as the Home minister) broke apart. Koirala then concentrated on developing the Nepali political structure. King Mahendra responded with a new constitution enabling free parliamentary elections to take place in 1959. Only a fragmented parliament was expected, but Koirala's Nepali Congress scored a landslide, taking more than two-thirds of the seats in the lower house. After several weeks of significant hesitation, Mahendra asked Koirala to form a government, which took office in May 1959.