Liberation theology was a radical movement that grew up in South America as a response to the poverty and the ill-treatment of ordinary people. The movement was caricatured in the phrase If Jesus Christ were on Earth today, he would be a Marxist revolutionary, but it's more accurately encapsulated in this paragraph from Leonardo.
Liberation theology said the church should derive its legitimacy and theology by growing out of the poor. The Bible should be read and experienced from the perspective of the poor.
The church should be a movement for those who were denied their rights and plunged into such poverty that they were deprived of their full status as human beings. The poor should take the example of Jesus and use it to bring about a just society.
Some liberation theologians saw in the collegiate nature of the Trinity a model for co-operative and non-hierarchical development among humans.
Most controversially, the Liberationists said the church should act to bring about social change, and should ally itself with the working class to do so. Some radical priests became involved in politics and trade unions; others even aligned themselves with violent revolutionary movements.
A common way in which priests and nuns showed their solidarity with the poor was to move from religious houses into poverty stricken areas to share the living conditions of their flock.