The Peruvian priest, Gustavo Gutiérrez, became its primary proponent[249] and, in 1979, the bishops' conference in Mexico officially declared the Latin American Church's "preferential option for the poor".[250] Archbishop Óscar Romero, a supporter of the movement, became the region's most famous contemporary martyr in 1980, when he was murdered while celebrating Mass by forces allied with the government.[251] Both Pope John Paul II and Pope Benedict XVI (as Cardinal Ratzinger) denounced the movement.[252] The Brazilian theologian Leonardo Boff was twice ordered to cease publishing and teaching.[253] While Pope John Paul II was criticized for his severity in dealing with proponents of the movement, he maintained that the Church, in its efforts to champion the poor, should not do so by resorting to violence or partisan politics.[249] The movement is still alive in Latin America today, though the Church now faces the challenge of Pentecostal revival in much of the region.[254]