How They Used To Hide Secret Messages 😮 (legend?)

He shaved the head, then began to tattoo a message directly onto his servant's scalp. After that, he rubbed a special paint into the wounds to color it. He then waited until his hair grew out completely, covering the tattoo. The servant was then sent to his allies, who shaved his head again, The servant was then sent to his allies, who shaved his head again, revealing the hidden message about the plans to rebel.