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).
Kalaratri
It is not uncommon to find the names, "Kali" and "Kalaratri" being used interchangeably, although these two deities are argued to be separate entities by some. Kali is first mentioned in Hinduism as a distinct goddess around 3000 BC. Chronologically then, Kaalratri (described textually in the Mahabharata, dated 3137 BC - 3067 BC) predates but most likely, informs, present representations of Kali.