Vikramaditya (IAST: ) was a legendary king mentioned in ancient Indian literature, featuring in traditional stories including those in Vetala Panchavimshati and Singhasan Battisi. Many describe him as ruler with his capital at Ujjain (Pataliputra or Pratishthana in a few stories). "Vikramaditya" was also a common title adopted by several monarchs in ancient and medieval India, and the Vikramaditya legends may be embellished accounts of different kings (particularly Chandragupta II). According to popular tradition, Vikramaditya began the Vikrama Samvat era in 57 BCE after defeating the Shakas, and those who believe that he is based on a historical figure place him around the first century BCE. However, this era is identified as "Vikrama Samvat" after the ninth century CE. Rajbali Pandey, Kailash Chand Jain and others believe that Vikramaditya was an Ujjain based Malava king. The Shakas advanced from Sindh to Malwa around the first century BCE, and were defeated by Vikramaditya. The Krita era, which later came to be known as Vikrama Samvat, marked this victory. Chandragupta II later adopted the title of Vikramaditya after defeating the Shakas. Proponents of this theory say that Vikramaditya is mentioned in works dating to before the Gupta era, including Brihathkatha and Gatha Saptashati. Vikramaditya cannot be based on Chandragupta II, since the Gupta capital was at Pataliputra (not Ujjain). According to Raj Pruthi, legends surrounding this first-century king gradually became intertwined with those of later kings called "Vikramaditya" (including Chandragupta II). Critics of this theory say that Gatha Saptashati shows clear signs of Gupta-era interpolation. According to A. K. Warder, Brihatkathamanjari and Kathasaritsagara are "enormously inflated and deformed" recensions of the original Brihatkatha. The early Jain works do not mention Vikramaditya and the navaratnas have no historical basis as the nine scholars do not appear to have been contemporary figures.