Travelling through the Terai today, it's hard to believe that this was once one of the most important places in the subcontinent. In 563 BC, the queen of the tiny kingdom of Kapilavastu gave birth to a son named Siddhartha Gautama and 35 years later, under a Bodhi tree at Bodhgaya in India, Buddhism was born. The Indian Buddhist emperor Ashoka made a famous pilgrimage here in 249 BC, leaving a commemorative pillar at the site of the Buddha's birth in Lumbini.
Nepal also played a pivotal role in the development of Hinduism. Sita, the wife of Rama and heroine of the Ramayana, was the daughter of the historical king Janak, who ruled large parts of the plains from his capital at Janakpur. Janak founded the Mithila kingdom, which flourished until the third century AD, when its lands were seized by the Gutpas from Patna in northern India.
The depopulation of the Terai began in earnest in the 14th century, when the Mughals swept across the plains of northern India. Hundreds of thousands of Hindu and Buddhist refugees fled up into the hills, many settling in the Kathmandu valley, which later rose to prominence as the capital of the Shah dynasty. Aided by legions of fearsome Gurkha warriors, the Shahs reclaimed the plains, expanding the borders of Nepal to twice their modern size.
Although the British never conquered Nepal, they had regular skirmishes with the Shahs. A treaty was signed in 1816 that trimmed the kingdom to roughly its current borders. Nepal later regained some additional land (including the city of Nepalganj) as a reward for assisting the British in the 1857 Indian Uprising.
The Terai was covered by swathes of jungle well into the 1950s. The indigenous people of the plains, the Tharu, lived an almost stone-age existence until 1954, when DDT was used to drive malaria from the plains and thousands of land-hungry farmers flocked into the Terai from India and the Nepali hills.
Today, the Tharu are one of the most disadvantaged groups in Nepal, and huge areas of the forest have been sacrificed for farmland and industrial development. Nevertheless, some large patches of wilderness remain, preserved in a series of excellent national parks, and the massive industrial and agricultural development in the plains is slowly raising the quality of life for the nation, at least in economic terms.