The last great king of the Gupta was Skanda Gupta was ascended the throne about 455 A.D. Even during the later years of Kumar Gupta's reign, the empire was attacked by a tribe called Pushyamitra but it was repulsed, And immediately after the accession of Skanda Gupta, Hunas made inroads, but they too were repelled.
However, fresh waves of Invaders arrived and shattered the fabric of the Gupta Empire. Although in the beginning the Gupta king Skanda Gupta tried effectively to stem the march of the Hunas into India, his successors proved to be weak and could not cope with the Huna invaders, who excelled in horsemanship and who possibly used stirrups made of metal, Although the Huna power was soon overthrown by Yasodharman of Malwa, the Malwa prince successfully challenged the authority of the Guptas and set up Pillars of victory commorating his conquest (AD 532) of almost the whole of northern India. Indeed Yasodharman's rule was short lived, but he dealt a severe blow to the Gupta empire.
The Gupta empire was further undermined by the rise of the feudatories. The governors appointed by the Gupta kings in north Bengal and their feudatories in Samatata or south-east Bengal broke away from the Gupta control. The later Gutpas of Magadha established their power in Bihar. Besides, the Maukharis rose to power in Bihar and Uttar Pradeshand had their capital at Kanauj. Proabably by AD 550 Bihar and Uttar Pradesh and passed out of gupta hands. And the rulers of Valabhi established their authority in Guajarat and Western Malwaa.
After the reign of Skanda Gupta (467 AD) any Gupta coin or inscription has been found in western Malwa and Saurashtra. The migration of guild of Silk weavers from Gujarata to Malwa in AD 473 and their adoption of non-productive professions show that there was not much demand for cloth produced by them. The advantages from Gujarat trade gradually disappeared. After the middle of the fifth century the Gupta kings made desperate attempts to maintain their gold currency by reducing the content of pure gold in it. The loss of western India complete by the end of the fifth century, must have deprived the Gutpas of the rich revenues from trade and commerce and crippled them economically, and the princes of Thaneswar established their power in Haryana and then gradually moved on to Kanauj.
The causes of the downfall of disappearence of the Guptas were basically not different from those that brought the end many ancient and medieval dynasties. Over and above the usual causes of administrative inefficiency, weak successors and stagnant the fall of the Guptas: dynastic dissensions, foreign invasions and some internal rebellions.
There is evidence to show that following the death of Kumaragupta and Skandagupta, there were civil wars and struggles for the throne. For instance, wehave the successors of Buddhagupta, highlighting the rule of more than just one king. Those were Vinayagupta in Bengal and Bhanugupta in Iran.
Absence of law of primogeniture along with strong centralized authority in ancient and medieval periods led to chaos. Thus we see that the resources of the empire were frittered away in petty squabbles and wars for the throne.
Besides circumstances weakening the Gupta monarchy, the very personalities of the later Gupta Kings contributed to the ultimate fall of this dynasty. They were not only men of weak character but also some of them followed pacifies that affected other spheres of administration, particularly that of military efficiency.
Foreign invasions was the second major factor in the decline and disappearance of the Gutpas. The invasion of barbaric tribe Pushyamitra was not the decisive. A far more important invasion was that of the White Huns, who, after settling in the Oxus vally, invaded India. First appeared during the reign of Budhagupta. Again they reappeared under the command of Toramana who annexed a large portion of the north-western region including parts of Moder U.P. He followed by hisson, Mihirakula, who became the overlord of north India. Indeed he was defeated by Yashodharman of Malwa but the repercussions of these invasions were disastrous for the Gupta Empire.
As a result of the weakning of Central Authoriy a number of feudal chieftans, principally those of the north-western region, assumed the status of independent rulers might more some names in this regard such as Maitrakas (of Kathiawar), Panivarajaks (of Budndhelkhand), Unchkalpas, Laxman in Allahabad. Etc.
After the reign of Buddhagupta, the status of certain, governors of North Bengal and Yamuna - Narmada area around Magadh too assumed independence and became to be known as the later Guptas.
By far one of the most important rebellions was that of Yashodharman of western Malwa who became independent and established his kingdom. He defeated Mihirakula and seams to have made extensive conquests from the Himalayas to Brahamputra. However, his empire did not last very long. Nevertheless, it set a pattern for other feudal cheiftans, who in due course, broke away from Central authority.
Last but not the least, we might note that the change in the Gupta polity from one of militancy to that of pacifism greatly affected the composition of the empire. We do have instances where some of the later Gupta kings who changed from Hinduism to Buddhism and this was reflected inmate total military inefficiency of the later Guptas.
Along with this development one more saboteur of political consciousness was the religious perception of ancient Indians. Beginning before the Christian are it came to be gradually established that the kingship has its own dharma known as rajya-dhrma while the people had a handul of dharmas like varnashrama dharma and the grihadharma. All these dharmas led the individual loyalty or perception towards a non-political entity. This thinking is given religious sanction by the priestly order. This thinking is given religious sanction by the priestly order of the day. Thus the State never was the architectonic factor in the life of ancient Indian except during the Mauryan era. It is this perception of ancient India that made the emergence and disappearance of hundreds of States mere non-events.