During the early period Kamboja was ruled by the kings but during the Kautiliya's time it transformed from a monarchy to republic. In the sixth century BC only 4 states -Kamboja, Vatsa, Kosala and Magadha survived. The political history of India from the 6th century BC onwards is the history of struggles between these states for supremacy. Ultimately the kingdom of Magadha emerged to be the most powerful and succeeded in founding an empire.