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).
Gildas
There are two different historical versions of the life of Gildas, the first written by an anonymous monk in the 9th century, and the other written by Caradoc of Llancarfan in the middle of the 12th century. Some historians have attempted to explain the differences in the versions by saying that there were two saints named Gildas, but the more general opinion is that there was only one St. Gildas and that the discrepancies between the two versions can be accounted for by the fact that they were written several centuries apart. The 9th century "Rhuys Life" is generally accepted as being more accurate.