Rivalry between Nepal and the East India Company—over the princely states bordering Nepal and India—eventually led to the Anglo-Nepalese War (1814–16). The Treaty of Sugauli was signed in 1816, ceding large parts of the Nepali territories of the Terai and Sikkim, which accounted to nearly one-third of the country, to the British in exchange for Nepalese autonomy. As the territories were not restored to Nepal by the British when freedom was granted to the people of British India, most of these lands later became a part of the Republic of India. Sikkim remained independent until annexed into India in 1975 when it becomes the 22nd state of the Republic of India. However, in 1860 the British returned the authority over some of Nepal's land in the Terai back to Nepal (known as "Naya Muluk", new country) as an act of gratitude for supporting Britain during various Indian uprisings, such as the Sepoy mutiny.