Liberation theology (, ) is a synthesis of Christian theology and socio-economic analyses, that emphasizes "social concern for the poor and political liberation for oppressed peoples." Beginning in the 1960s after the Second Vatican Council, liberation theology became the political praxis of Latin American theologians such as Gustavo Gutiérrez, Leonardo Boff, and Jesuits Juan Luis Segundo, and Jon Sobrino, who popularized the phrase "preferential option for the poor." This expression was used first by Jesuit Fr. General Pedro Arrupe in 1968 and soon after this the World Synod of Catholic Bishops in 1971 chose as its theme "Justice in the World".