The Epthalite branch of the Huns entered through the northwestern gate of India in fifth century A.D. Consolidating their base in Afghanistan and the capital in Bamiyan, they tried to invade India. About 458 A.D., they entered Punjab and the failure of the Guptas to guard the northeast frontier of the Empire led the Huns to an unopposed entrance in the Gangetic valley, the heart of the Gupta Empire. However the invasion by Toraman was completely unsuccessful against the Guptas because the Gupta Emperor Skandagupta inflicted a crushing defeat upon them and pushed them out of their frontier. The Huns suffered a great loss. According to some scholars, it was due the tough resistance against the Huns by the Guptas and the Chinese kings that the main tide of the Hun invasion turned back towards the European countries.
However, the Hun invasion suppressed by Skandagupta did not completely perish the tribe. These notorious warlike tribes renewed their invasion against the strong foundation of the Gupta Empire. But the later Gupta emperors were not powerful enough to protect the northeastern frontier of the Gupta Empire from fresh incursions of the Huns. The Huns under Toraman poured in once again through the Hindukush passes. During this phase of invasion, Toraman conquered Punjab, Rajputana and Malwa. He concentrated his base in Punjab and from there controlled his operation in the interiors of India. He reduced a number of local kings as his vassals and he assumed the title of "Maharajadhiraja". His coins and inscriptions are found in extensive regions of Sutlej and Yamuna. It is known from numismatics and epigraphic evidences that Toraman had his sway over the regions of Punjab, Rajputana, Malwa, Kashmir and parts of Doab. Some of the Gupta provincial governors also joined Toraman during the course of his invasion in India. However Toraman's ascendency in India did not last long. He ruled from 510 to 511 A.D. Bhanu Gupta, a scion of the Gupta House and his feudatory Gopalachandra, challenged Toraman's dominance in India. They inflicted a humiliating defeat upon him, which forced him to retreat to the other side of India.
Toraman was succeeded by his son Mihirkula. He was a Hinduised Hun and from his coins it is evident that he was a Saiva. Mihirkula was a notorious warrior like his father and killed people, demolished Buddhist temples and also devastated towns and cities. From Punjab Mihirkula tried to dominate on Rajputana and Malwa. In this course of his victorious march, he came in conflict with the Guptas and their feudatories. From the inscription of Mihirkula belonging to his 15th reigning year, it is known that Yasodharmana, a feudatory of the Guptas had imposed a severe crush on Mihirkula. At that time Mihirkula was engaged in terrible warfare with Baladitya. It is presumed by historians that perhaps after the death of Yasodharmana, Mihirkula had started a fresh attack on the Gupta territory. Hiuen Tsang had identified Baladitya as Narasimha Gupta and also suggested that Narasimha Gupta successfully had defeated the Hun chief and permitted him to leave the Gupta Territory. According to historians, the struggle between Mihirkula and the Gupta chief Baladitya was not merely political, it has a religious shade also. It is suggested that the anti-Buddhist activities of Mihirkula had magnified the dimension of his conflict with Mihirkula.
Perhaps after this defeat Mihirkula had concentrated his authority in the regions of Punjab. The inscription of Mihirkula states that he had built the Sun temple and the Buddhist monastery. There is keen controversy among the scholars regarding the facts provided by the inscription of Mihirkula. This is because, a group of historians have suggested that Mihirkula was prejudiced against Buddhism, which had led him to war against Narasimha Gupta. But according to another group of writers, a destroyer of Buddhism could not establish Buddhist monasteries in the latter part of his career. Henceforth there is still a keen controversy over the subject that whether Mihirkula was a destroyer of Buddhism or not.
However the significance of Hun invasion in India had far reaching effects. The Huns had destroyed the precarious hold of the Gupta sovereign on their feudatories. As the Guptas were busy in their resistance against the Huns, their hold on the semi-independent feudatories was weak. Petty kingdoms began to flourish on the ruins of the Gupta Empire. Hence the political unity established by the early Guptas was completely shattered during the time of the later Guptas. Moreover the Hun inroads in western and central India had upset the trade of the Guptas in India with the Roman Empire, which led to the devastation of the Gupta economy. As a result the economic and cultural cities like Ujjaini or Pataliputra lost their significance and glory. There was total dislocation of the socio-political and economic life during the later Guptas caused by the Hun invasion. The debased Gupta coins bear testimony to this fact. But the Hun invasion in India had positive effects also. With the decline of trade relations with the Roman Empire through West Indian ports, trade with South East Asia and China was vastly prospered through ports like Kaveri Pattanam, Tamralipta etc.
The more significant effect of the Hun invasion was the racial admixture. When the Huns had appeared in India, there was an elaborate racial movement. The Huns had thrown open the gates of northwest, through which various other tribes apart from the Huns had also poured into the land. They adopted the Hindu religion and completely merged with the bulk of the Indian population. The Huns and other martial cultures introduced the Indian society to their vigour and warlike culture. Thus the Hun invasion led to socio-economic and cultural transformation of the Indian society as a whole.