Background: Aryan tribes from the northwest infiltrated onto the Indian subcontinent about 1500 B.C.; their merger with the earlier Dravidian inhabitants created the classical Indian culture. The Maurya Empire of the 4th and 3rd centuries B.C. - which reached its zenith under ASHOKA - united much of South Asia. The Golden Age ushered in by the Gupta dynasty (4th to 6th centuries A.D.) saw a flowering of Indian science, art, and culture. Arab incursions starting in the 8th century and Turkic in the 12th were followed by those of European traders, beginning in the late 15th century. By the 19th century, Britain had assumed political control of virtually all Indian lands. Indian armed forces in the British army played a vital role in both World Wars. Nonviolent resistance to British colonialism led by Mohandas GANDHI and Jawaharlal NEHRU brought independence in 1947. The subcontinent was divided into the secular state of India and the smaller Muslim state of Pakistan. A third war between the two countries in 1971 resulted in East Pakistan becoming the separate nation of Bangladesh. India's nuclear weapons testing in 1998 caused Pakistan to conduct its own tests that same year. Despite impressive gains in economic investment and output, India faces pressing problems such as significant overpopulation, environmental degradation, extensive poverty, and widespread corruption.