The National Portrait Gallery, London
The world has learned so much from the writings of the famous English diarist Samuel Pepys, who recorded his daily life for almost ten years. He first mentioned drinking tea in his diary entry for September 25, 1660. He wrote that he had been discussing foreign affairs with some friends, 'And afterwards did send for a Cupp of Tee (a China drink) of which I never drank before'.
Since Pepys was a member of the wealthy and fashionable London set, his failure to mention tea earlier suggests that it was still unusual at this time. This was soon to change.
By the way, you can find Pepys' complete diary (1660-1669) online, where there are many more references to tea.
(Purchase the Samuel Pepys print here)