The political factor was the rise during the 7th century B.C. of the Kosala power.
The welding together of the great Kosala kingdom, more than twice the size of England, in the very centre of the settled country, led insensibly but irresistibly to the establishment of a standard of speech, and the standard followed was the language used at the court at Savatthi in the Nepalese hills, the capital of Kosala.
The name here used by the chronicler for Pali is "the Magadhi tongue," by which expression is meant, not exactly the language spoken in Magadha, but the language in use at the court of Asoka, king of Kosala and Magadha.
Of these the most important was that of the Haihayas of Ratanpur, a family which, settled from time immemorial in the Nerbudda valley, had towards the close of the 10th century succeeded the Pandava dynasty of Maha Kosala (Chhattisgarh) and ruled, though from the 16th century onwards over greatly diminished territories, until its overthrow by the Mahrattas in 1745.
The first king, Gnya-khri btsan-po, is said to have been the fifth son of King Prasenajit of Kosala, and was born with obliquely drawn eyes.
He seems to have been born in the south of India, and to have lived under the patronage of a king of southern Kosala, the modern Chattisgarh.
The Sakiyas were still a republic. They had republics for their neighbours on the east and south, but on the western boundary was the kingdom of Kosala, the modern Oudh, which they acknowledged as a suzerain power.
It is said to have covered an area of 96 m., and was the capital of the kingdom of Kosala, the court of the great king Dasaratha, the fifty-sixth monarch of the Solar line in descent from Raja Manu.
Kosala is also famous as the early home of Buddhism, and of the kindred religion of Jainism, and claims to be the birthplace of the founders of both these faiths.
About the beginning of the 6th century B.C. the settled country between the Himalaya mountains and the Nerbudda river was divided into sixteen independent states, some monarchies and some tribal republics, the most important of which were the four monarchies of Kosala, Magadha, the Vamsas and Avanti.
Kosala, the modern kingdom of Oudh, appears to have been the premier state of India in 600 B.C. Later the supremacy was reft from it by the kingdom of Magadha, the modern Behar (q.v.).
South of Kosala lay the kingdom of the Vamsas, and south of that again the kingdom of Avanti.
The principal cities of India at this date were Ayodhya, the capital of Kosala at the time of the Ramayana, though it after wards gave place to Sravasti, which was one of the Capital cities.
The home of early Buddhism was round about Kosala and Magadha; in the district, that is to say, north and south of the Ganges between where Allahabad now lies on the west and Rajgir on the east.