Membership of the Secular Franciscan Order includes lay men and women as well as diocesan priests. A number of Popes have been members of this Order. Professed members use the letters OFS after their name in line with the official name of the Order. The current rule was given by Pope Paul VI in 1978 with the Apostolic letter "Seraphicus Patriarcha". It is designed to adapt the Secular Franciscan Order to the needs and expectations of the Church in the conditions of changing times.