The empire gradually declined due in part to loss of territory and imperial authority caused by their own erstwhile feudatories, and from the invasion by the Hunas from Central Asia. After the collapse of the Gupta Empire in the 6th century, South Asia was again ruled by numerous regional kingdoms. A minor line of the Gupta clan continued to rule Magadha after the disintegration of the empire. These Guptas were ultimately ousted by the Vardhana king Harsha, who established an empire in the first half of the 7th century.