If a mendicant woman is stopped at the entrance, the line of door-keepers., spies under the guise of father and mother, women artisans, court-bards, or prostitutes shall, under the pretext of taking in musical instruments, or through cipher-writing, or by means of signs, convey the information to its destined place.
—Kautilya, in the Arthaśāstra, 1.12:13
