Tipton in a 2008 historical perspectives review, states that uncertainty remains on dating the text, how many authors contributed to it and when. Estimates range from 1000 BCE, 800–600 BCE, 600 BCE, 600–200 BCE, 200 BCE, 1–100 CE, and 500 CE. Partial resolution of these uncertainties, states Tipton, has come from comparison of the Sushruta Samhita text with several Vedic hymns particularly the Atharvaveda such as the hymn on the creation of man in its 10th book, the chapters of Atreya Samhita which describe the human skeleton, better dating of ancient texts that mention Sushruta's name, and critical studies on the ancient Bower Manuscript by Hoernle. These information trace the first Sushruta Samhita to likely have been composed by about mid 1st millennium BCE.