The Gupta Empire started after the Mauryian empire in 280ad. the gupta empire was the golden age of India. it brought us the decimal system, Arabic numerals, and the concept of zero. Disintegration of the Maurya Empire and the invasions were mitigated by a continuing trade in which Indians sold more to the Roman Empire than they bought, with Roman coins piling up in India. The Kushan invaders were absorbed by India, Kushan kings adopting the manners and language of the Indians and intermarrying with Indian royal families. The southern kingdom of Andra conquered Mashhad in 27 BCE, ending the rule Sunga dynasty there, and it extended its power in the Ganges Valley, creating a new bridge between the north and the south. But this came to an end as Andhra and two other southern kingdoms weakened themselves by warring against one another. By the early 300s, power in India was returning to the Mashhad region, and India was entering what would be called its classical age.