Pope Francis' visit to the heavily indigenous Mexican state of Chiapas appears aimed at celebrating the region's "Indian church," a mix of Catholicism and indigenous culture once considered a thorn in the side of standard liturgy by the Vatican.

The inclusion of pine boughs and eggs, the Mayan faithful's references to "God the Father and Mother" and the use of indigenous elements in Masses long caused church officials to bristle.

Not so with history's first Latin American pope, who the Vatican said will present a decree during his Feb. 15 visit authorizing the use of indigenous languages. The Chiapas Mass itself would include readings and songs in three different indigenous languages.

"Within the church there have always been errors," said Felipe Arizmendi, the Bishop of San Cristobal de las Casas, the colonial city where Francis will preside over Mass. "So we recognize that many times, we have not given them (the indigenous) their place."

Francis' visit comes amid strong challenges to the church in the southern state, including huge inroads by evangelical Protestants and grinding poverty in a region rich with coffee, Mayan ruins, pine-covered hills and jungles. Chiapas has the high poverty rate in Mexico at 76.2 percent.

The challenges have always included the church's relations with indigenous communities who have struggled for centuries to maintain their traditions and independence, sometimes embracing and sometimes clashing with the hierarchy.

Religious practices in some communities encourage rampant alcohol abuse, crushing debts and autocratic local bosses known as "caciques."

"Traditional" Catholic towns often require impoverished residents to go into debt to pay for annual, alcohol-fueled festivals for the local patron saint. Most of the food, drink, flowers and fireworks for the festivals are bought from the local bosses, who sell them to residents on credit at usurious rates.

In some communities, residents have expelled or ostracized any inhabitant who converts to Protestantism, often taking their lands or possessions, or denying them access to basic services like water or electricity.

Abdias Tovilla Jaime, an evangelical pastor at Chiapas' Revived Presbyterian Church, said the tactic doesn't appear to work; only 58 percent of Chiapas residents said they were Catholic in 2010, well below the national average of 83 percent.

"It is strange, we have seen the biggest growth in evangelical Christians in Chiapas in the towns where they are persecuted," Tovilla Jaime said.

Francis' embrace of at least some of Chiapas' indigenous versions of Catholicism is consistent for a pontiff who hasn't shied away from honoring causes and clerics who once ran afoul of Vatican authorities, often for putting into practice the church's "preferential option for the poor." During his 2015 visit to Bolivia, Francis prayed at the site where a Jesuit proponent of liberation theology was tortured and killed by paramilitary squads.

In Chiapas, Francis is scheduled to visit the diocese of San Cristobal, home to two of the most famed religious defenders of indigenous people in Mexican history: Bishops Bartolome de las Casas in the 16th century and Samuel Ruiz, who died in 2011.

Both were beloved by indigenous people and widely reviled among the wealthy classes and much of the church hierarchy. Many officials accused Ruiz of acting on behalf of the Zapatista rebels in their 1994 uprising for greater indigenous rights.

Part of the liberation theology movement that swept Latin America after the Second Vatican Council in the early 1960s, Ruiz tried to fend off the rapid growth of Protestant denominations by adapting to indigenous customs.

One of his controversial measures was to rely heavily on married male lay workers because local culture granted more respect to men with children than to childless, celibate men such as priests. Some in the church worried the married deacons were taking on priestly functions.

In 2002, under Pope John Paul II, the Vatican council asked the Chiapas diocese to halt deacon ordinations. But under Francis, the ordinations were renewed.

"Still today, and not just in Chiapas but in other parts of Mexico and Latin America, some people don't take into account their (indigenous) languages, their customs, their rites, they despise all that as if it were something backward, when in fact they have a great wisdom. You just have to get close to them to know it," Bishop Arizmendi said.