It is known from archaeological evidence that a highly sophisticated urbanized culture—the Indus civilization—dominated the northwestern part of the subcontinent from about 2600 to 2000 BCE. From that period on, India functioned as a virtually self-contained political and cultural arena, which gave rise to a distinctive tradition that was associated primarily with Hinduism, the roots of which can largely be traced to the Indus civilization. Other religions, notably Buddhism and Jainism, originated in India—though their presence there is now quite small—and throughout the centuries residents of the subcontinent developed a rich intellectual life in such fields as mathematics, astronomy, architecture, literature, music, and the fine arts.Throughout its history, India was intermittently disturbed by incursions from beyond its northern mountain wall. Especially important was the coming of Islam, brought from the northwest by Arab, Turkish, Persian, and other raiders beginning early in the 8th century CE. Eventually, some of those raiders stayed; by the 13th century much of the subcontinent was under Muslim rule, and the number of Muslims steadily increased. Only after the arrival of the Portuguese navigator Vasco da Gama in 1498 and the subsequent establishment of European maritime supremacy in the region did India become exposed to major external influences arriving by sea, a process that culminated in the decline of the ruling Muslim elite and absorption of the subcontinent within the British Empire.Direct administration by the British, which began in 1858, effected a political and economic unification of the subcontinent. When British rule came to an end in 1947, the subcontinent was partitioned along religious lines into two separate countries—India, with a majority of Hindus, and Pakistan, with a majority of Muslims; the eastern portion of Pakistan later split off to form Bangladesh. Many British institutions stayed in place (such as the parliamentary system of government); English continued to be a widely used lingua franca; and India remained within the Commonwealth. Hindi became the official language (and a number of other local languages achieved official status), while a vibrant English-language intelligentsia thrived.