I want to know the answer to the following question:
What is the earliest recorded instance of circadian rhythm?
All the background I'm provided with is that "The observation of a circadian or diurnal process in humans is mentioned in Chinese medical texts dated to around the 13th century, including the Noon and Midnight Manual and the Mnemonic Rhyme to Aid in the Selection of Acu-points". Is that enough to answer the question?
Answer: no