Encyclical, << ehn SIHK luh kuhl or ehn SY kluh kuhl, >> is a letter from a Christian leader, particularly the pope, which is intended for general distribution among churches. The term originally applied to some of the letters written by Saint Paul and early church writers called Apostolic Fathers that were sent to many churches. After the time of the Apostolic Fathers, bishops wrote encyclicals to the churches in their care. In modern times, encyclical has come to mean a letter written by the pope to Roman Catholic churches worldwide. These letters have addressed such topics as church teachings, church discipline, current social and moral issues, peace, the rights of workers, and the plight of people living under oppression. See also Bull.