The Islamic Republic of Pakistan marks the area where South Asia converges with Southwest Asia and Central Asia. The earliest known civilization of South Asia—the Indus Valley civilization—was located in the area of present-day Pakistan. Over the course of history, the land was part of the Mughal Empire and then fell under British rule. When British India was partitioned into predominately Muslim and Hindu states, Pakistan gained independence with two geographically separate areas. Eventually, East Pakistan seceded from West Pakistan and became the independent republic of Bangladesh. Due to the fact that the country lies in an area that was invaded repeatedly during its history, the people of Pakistan are ethnically diverse, although an overwhelming majority of the population is Muslim. The migration of refugees from Afghanistan and Muslims from India has notably altered the demographics of the area. As a result, the Pakistani population can trace their ethnicity to Dravidian, Indo-Aryan, Greek, Scythian, Hun, Arab, Mongol, Persian, Baluchi, and Afghan roots. Overall, ethnic identity is multilayered and complex based on a combination of religion, language, ethnicity, and tribe. Politically, Pakistan is focused on its security concerns with India, the Kashmir dispute, and its striving to develop a sustainable democracy as a progressive Muslim state.