Magadha formed one of the sixteen mahajanapadas (Sanskrit: "Great Countries") of ancient India. The core of the kingdom was the area of Bihar south of the Ganges; its first capital was Rajagriha (modern Rajgir), then Pataliputra (modern Patna). Rajagriha was initially known as 'Girivrijja' and later came to be known as so during the reign of Ajatashatru.