Kālidāsa
The most popular theory is that Kalidasa flourished during the reign of Chandragupta II, and therefore lived around 4th-5th century CE. Several Western scholars have supported this theory, since the days of William Jones and A. B. Keith. Many Indian scholars, such as Vasudev Vishnu Mirashi and Ram Gupta, also place Kalidasa in this period. According to this theory, his career might have extended to the reign of Kumaragupta I (r. 414 – 455 CE), and possibly, to that of Skandagupta (r. 455 – 467 CE).
Kali Yuga
The Brahma-vaivarta Purana has words spoken by Lord Krishna to Mother Ganga just before the beginning of the Kali Yuga (the age of quarrel and strife). The Kali Yuga began approximately five thousand years ago, and it has a duration of 432,000 years, leaving us with 427,000 years until the end of the present age. Within this 432,000 year period, there is a period of 10,000 years that will be peaceful. That golden age is being described below by Lord Sri Krishna. Predicted in Brahma-vaivarta Purana 4.129. The fourth part of the Brahma-vaivarta is called Kṛṣṇa-janma-khanda. Chapter 129 is called Golokarohanam, because it describes how Krishna returns to His abode. This specific dialogue is between Lord Krishna and Mother Ganga. Verse 49 is a question by Ganga, verses 50–60 are Lord Sri Krishna's answer.