LIMA, Peru (AP) — Peruvian theologian the Rev. Gustavo Gutiérrez, the father of the social justice-centered liberation theology that the Vatican once criticized for its Marxist undercurrents, has died. He was 96.

The Dominican Order in Peru announced on social media that the Catholic priest died Tuesday night at a convent in Lima, the South American country’s capital. It did not give a cause of death.

Gutiérrez’s liberation theology put the poor as its priority and exerted great influence on doctrine and the history of the church in Latin America. His 1971 book “A Theology of Liberation” had a profound impact by proposing a faith based on social justice focused on the poor and positing that poverty “is a scandalous state, an attack on human dignity, and therefore, contrary to the will of God.”

“We thank God for having had a faithful theologian priest who never thought about money, or luxuries, or anything that seemed to make him superior,” Cardinal and Archbishop of Lima Carlos Castillo said in a statement following Gutiérrez’s death. “Small as he was, he knew how to announce the Gospel to us with strength and courage in his smallness.”

Gutiérrez’s thinking attracted many who were outraged by the inequality and dictatorships in several Latin American countries in the 1960s and 1970s. But his ideals were severely criticized by the Vatican, which spent decades disciplining some of its most vocal supporters.

Gutiérrez, who himself was never disciplined, told reporters in 2015 that liberation theology as a whole was never condemned, but he acknowledged that the Holy See had engaged in “very critical dialogue” with its proponents and that there were “difficult moments.”

The Vatican objected to liberation theology’s basis in Marxist analysis of society — particularly the idea of class struggle in the promotion of social, political and economic justice for the poor. Some versions of liberation theology are at variance with church teachings because they view Christ as a mere social liberator.

The arrival of the first Latin American pope, Pope Francis, focused the Vatican’s attention on social justice and the poor and led to something of a rehabilitation of liberation theology.

“I think in this moment, the climate surrounding this theology is different. That is true,” Gutiérrez told reporters at the time.

When he turned 90 in 2018, Pope Francis wrote him a letter thanking him for his contributions to “the Church and to humanity, through your theological service and your preferential love for the poor and the discarded of society.”

Gutiérrez was born in Lima on June 8, 1928. He earned a doctorate in theology from the Catholic University of Lyon. In addition to his theological work, Gutiérrez served a parish in a Lima neighborhood for more than two decades.