India in the Ancient World.

The Indian subcontinent forms a cohesive territorial mass, protected by the lofty peaks of the Himalayas in the north, surrounded by the Arabian Sea, the Bay of Bengal, and the Indian Ocean on the west, east, and south respectively. Because of the Himalayas, invasion of ancient India was sporadic, accomplished by small numbers of people hardy enough to venture through the mountain passes. This ensured the continuity of Indian civilization and the survival of its basic culture and religious traditions throughout history. Those who migrated, invaded, or sought refuge in India eventually assimilated into the mainstream while retaining parts of their distinctive cultures.