Why is the Gupta Age called the Classical Age?

The Gupta Empire, although short-lived, did manage to
consolidate most of northern India and present day Eastern Pakistan into a united
empire. After the collapse of the Gupta Empire, India was not re-united for several
hundred years. The time of the Gupta Empire is referred to as the "Golden Age of India"
because of numerous artistic, religious, and architectural developments. A number of
scholars were active in this period which resulted in the advancement of science and
knowledge. An extensive trade network was also established. Among its accomplishments
were the concept of zero and the idea of a heliocentric solar system. The game of Chess
is said to have originated during the Gupta Empire.There is some belief that during this
empire a number of religious works explaining the doctrines of Buddhism, Hinduism and
Jainism were created. The Gupta Empire was thus the first Empire that could be
positively identified as uniquely Indian. Its contributions are still part of much of
modern Indian culture.