A brief presentation of new research into the Arab term of madjus ('magician'), that comes from the name for religious characters in pre-Islamic Persian Zoroastrianism, but which is sometimes found in Arab texts applied to "ethnic" minorities in contact with Islam in the Muslim west. Some texts are analysed and the evolution of the word is studied. It appears that it was only related to Zoroastrianism to deal with populations that were neither Muslim, Christian, Jewish nor idolaters. This was a category of people who the Muslim political powers, in their early conquests, in the 7th and 8th centuries, attributed a juridical status of "protected by Islam" (ahl al-dhimma) of second class, as they had no prophet, holy book or religious heads of...