The phrase appears in Jean-Jacques Rousseau's Confessions, which credit it to 'a great princess' in a passage written in the 1760s. Marie Antoinette, born in 1755, was then a child living in Vienna: she only arrived in France in 1770. No contemporary source puts the words in her mouth. They were pinned on her much later, as shorthand for a court out of touch with the people. And the original word was brioche, not cake.
Around 2300 BCE, Enheduanna, daughter of King Sargon of Akkad, became high priestess of the Moon god at Ur. She composed hymns to the goddess Inanna and put her name to them. She is the oldest person identified as the author of a literary work, about 1,500 years before Homer.
Squeeze Earth's 4.5 billion years into a single 24-hour day. Homo sapiens shows up around 11:59:54 p.m., roughly six seconds before midnight. All of written history, from Sumerian tablets to today, fits into the final tenth of a second. A cosmic blink.