There is no historical evidence to show that these nine scholars were contemporary figures or proteges of the same king. Vararuchi is believed to have lived around 3rd or 4th century CE. The period of Kalidasa is debated, but most historians place him around 5th century CE. Varahamihira is known to have lived in 6th century CE. Dhanavantari was the author of a medical glossary (Nighantu); his period is uncertain. Amarasimha cannot be dated with certainty either, but his lexicon utilizes the works of Dhanavantari and Kalidasa; therefore, he cannot be dated to 1st century BCE, when the legendary Vikramaditya is said to have established the Vikrama Samvat in 57 BCE. Not much is known about Shanku, Vetalabhatta, Kshapanaka and Ghatakarpara. Some Jain writers identify Siddhasena Divakara as Kshapanaka, but this claim is not accepted by historians.