Summary — In this article the Author tackles the problem of the original « cle-i icality» of the Order of Friars Minor, since it is historically proved that St. Francis and his first companions had received the « tonsure », but it is not easy to explain the exact meaning of this event. It is a problem which concerns not only the Order of Friars Minor, but also all the other religious Orders founded on the institution of apostolic religion, sanctioned by the Lateran Ecumenical Council IV of 1215. It is not possible to understand the clerical or lay nature of the apostolic Orders, if one does not understand the nature of the institution of apostolic religion. In this context, the Author investigates the original clericality of the Order of Friars Minor, as witnessed in the « Franciscan Sources », and afterwards an enquiry is made on the significance of the term « cleric » through the lapse of the centuries. From a deep study of the concept of « ministerial cleric» the Author proceeds to give his own interpretation of the testimonies contained in the Franciscan Sources regarding the original clericality of the Order of Friars Minor. The Author arrives to the conclusion that the Order of Friars Minor, because of its origins and its particular lole within the extension of the institution of apostolic religion, is neither a clerical nor a lay Order, but simply an apostolic Order, with equal rights and duties within the community, open to both clerical and lay friars.