Write a detailed long answer on : The Classical Age of the Gupta Empire/Age.

The Classical Age of the Gupta Empire, also known as the Golden Age of India, was a period of great cultural and scientific advancements, marked by extensive inventions and discoveries in science, technology, engineering, art, dialectic, literature, logic, mathematics, astronomy, religion, and philosophy that crystallized the elements of what is generally known as Hindu culture.

The Gupta Empire was established around the mid-to-late 3rd century AD and lasted until the 6th century AD. The empire covered much of the Indian subcontinent, with its capital at Pataliputra (modern-day Patna). The empire was founded by Sri Gupta, but it was his successors, particularly Chandragupta I, Samudragupta, and Chandragupta II who are credited with the significant achievements of this period.

The Gupta period is known for its significant achievements in arts and sciences. The period saw great advancements in literature, with the famous Sanskrit playwright Kalidasa, who wrote plays like 'Abhijnanasakuntalam', 'Vikramorvasiyam' and 'Malavikagnimitram', being a part of the Gupta court. The period also saw the composition of the 'Puranas', a genre of important Hindu religious texts.

In the field of science, the concept of zero, the decimal system, and the area of a triangle were developed during the Gupta period. Aryabhata, the famous astronomer and mathematician, was also part of the Gupta court. He wrote 'Aryabhatiya', where he covered topics like algebra, trigonometry, and astronomy.

In terms of architecture, the Gupta period saw the construction of the rock-cut Ajanta Caves and the temples of Khajuraho, which are UNESCO World Heritage Sites. The period also saw advancements in painting, with the frescoes of Ajanta Caves being the perfect examples of the same.

The Gupta period also saw a tolerant religious atmosphere. Hinduism saw a revival during this period, but Buddhism and Jainism were also practiced freely. The period saw the construction of both Hindu temples and Buddhist stupas.

In conclusion, the Gupta Empire or the Classical Age was a period of great advancements in various fields. It was a period when culture, science, and arts flourished, and it laid the foundation for much of the knowledge that we have today. The Gupta Empire was not just a political empire, but an empire of the mind, of culture, and of intellectual achievement.