The word Arsenic is borrowed from the Persian word Zarnikh meaning "yellow orpiment". Zarnik was borrowed by Greek as arsenikon. Arsenic has been known and used in Persia and elsewhere since ancient times. As the symptoms of arsenic poisoning were somewhat ill-defined, it was frequently used for murder until the advent of the Marsh test, a sensitive chemical test for its presence. (Another less sensitive but more general test is the Reinsch test.) Due to its use by the ruling class to bump each other off and its incredible potency and discreteness, arsenic has been called the the Poison of Kings and the King of Poisons.