The attack of the White Huns in the 5th century Flagged the decline and end of the Gupta golden years, even though at first, Gupta crushed them.
After the collapse of the Gupta empire, north India separated into the various number of small Hindu kingdoms and was not really united again until the advance of the Muslims.
White Huns destroyed the cities and reduced the Hindu temples. Feudal provinces were declared independence when the Gupta are destroyed.