The history of tea spreads across multiple cultures over the span of thousands of years. Tea originated in southwest China, likely the Yunnan region during the Shang dynasty as a medicinal drink. An early credible record of tea drinking dates to the 3rd century AD, in a medical text written by Hua Tuo. It first became known to western civilization through Portuguese priests and merchants in China during the early 16th century. Drinking tea became popular in Britain during the 17th century. The British introduced tea production, as well as tea consumption, to India, in order to compete with the Chinese monopoly on tea.