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).
Navaratnas
However, "Jyotirvidabharana" is considered a literary forgery of a date later than Kalidasa by multiple scholars. V. V. Mirashi dates the work to 12th century, and points out that it could not have been composed by Kalidasa, because it contains grammatical faults. There is no mention of such "Navaratnas" in earlier literature. D. C. Sircar calls this tradition "absolutely worthless for historical purposes".