However, according to Herodotus, Histiaeus was unhappy having to stay in Susa, and made plans to return to his position as King of Miletus by instigating a revolt in Ionia. In 499 BC, he shaved the head of his most trusted slave, tattooed a message on his head, and then waited for his hair to grow back. The slave was then sent to Aristagoras, who was instructed to shave the slave's head again and read the message, which told him to revolt against the Persians. Aristagoras, who was disliked by his own subjects after an expedition to Naxos ended in failure, followed Histiaeus' command, and with help from the Athenians and Eretrians, attacked and burned Sardis. When Darius learned of the revolt, he sent for Histiaeus, who pretended to have no knowledge of its origins, but asked to be sent back to Miletus to put down the revolt. Herodotus writes that Darius permitted him to leave.