Every year, millions of Mexican pilgrims make their way to the Basilica of Our Lady of Guadalupe, where they venerate a brown-skinned virgin. Catholics believe the virgin Mary appeared to an indigenous farmer at that very site in northern Mexico City – once a temple to the Aztec goddess Tonantzin and now the world’s most-visited Marian shrine.  Related: Pope's focus on violence and poor likely to make for 'uncomfortable' Mexico visit  Next week, Pope Francis will make his own pilgrimage to the basilica, saying he couldn’t come to Mexico without visiting “La Virgencita”. It’s likely to go down as the least controversial part of a six-day trip in which he is expected to cause discomfort for the church and political class by speaking about subjects they have largely stayed silent on such as security, violence and inequality.  Mexicans may express misgivings of their political leaders and church hierarchy, but never of Our Lady of Guadalupe. Nearly 500 years after the apparition, 83% of the population still self-identifies as Catholic – but the number is in steady decline, as believers defect to evangelical congregations.  Catholicism arrived in Mexico with the conquistadors coming to plunder the country, but it took the apparition of Mary in 1531 for the religion to take root. Historians say the Spanish cleverly substituted the Virgin for Tonantzin and employed her to evangelize the indigenous populations. That syncretism converted the masses, who went on to develop a unique form of Catholicism, in which rabid religiosity and popular piety are expressed, but the sacramental and social side of the faith are often ignored.  It’s hard to overestimate the religion’s impact in Mexican history, even though church and state were estranged for most of the last century and relations with the Vatican were only restored in 1992. Priests played prominent roles in Mexico’s past, too, although they are technically forbidden today from talking politics.  Mexican independence was ignited by a parish priest: Miguel Hidalgo, who inspired an uprising with his cry of “¡Viva México!”  The church enjoyed a privileged position in the newly independent Mexico, where only Catholics could be counted as citizens. But that ended with the rise of the liberals in the 1850s and indigenous president Benito Juárez, whose reform laws confiscated church properties, subordinated church courts to civilian authorities and prohibited priests from wearing clerical dress in public.  The church responded by supporting conservatives’ efforts to bring in Austrian archduke Maximilian, backed by French forces, as emperor in 1863. He was captured and executed by liberal forces in 1867.  “This was a church that supported independence, then invited an empire to invade Mexico,” said Ilán Semo, political historian at the Jesuit-run Iberoamerican University.  The Mexican revolution of 1910 brought about more conflict for the Catholic church: the country’s new leaders feared that religion would hold back progress, and imposed even stricter anti-clerical laws – such as a prohibition on preaching politics from the pulpit – prompting Pope Pius XI to write in a 1926 encyclical that priests were put in the same category as “criminals and the insane”.  The crackdown inspired another uprising – this time the Catholic insurgency known as the Cristero rebellion. In recent years the rebels’ martyrs have been canonized and one, Santo Toribio Romo, has been adopted as the unofficial patron saint of migrants heading north to the US.  The uprising left a shortage of priests, but a faithful following, who fashioned a homespun religion, practiced in private, of praying the rosary, venerating the virgin and their chosen saints, and baptizing their children, though not attending mass or receiving the sacraments.  “There is a lot of religiosity and little commitment,” said priest and historian Father Manuel Olimón.  Social commitment is often lacking in modern Mexican Catholicism, he said: corrupt politicians, tight-fisted businessmen and cartel kingpins all consider themselves proper Catholics.  In the absence of priests, popular piety and folk religion took hold, persisting today in Mexicans’ fondness for pseudo-saints such as the skeletal-looking Santa Muerte – condemned as satanic by church leaders, but seen as “a speedy, efficacious, multitasking miracle-worker”, with an estimated 10 million devotees worldwide, according to Andrew Chesnut, religious studies professor at Virginia Commonwealth University.  Related: Inside Santa Muerte, Mexico's cult of death - in pictures  “She’s the saint who doesn’t discriminate in a Mexico in which classism, sexism and homophobia are deeply entrenched,” said Chesnut, author of the book Devoted to Death.  “As the saint of death, she resonates in a Mexico of so much death and dying over the past few years.”  As drug war violence has escalated over the past decades, church officials have mostly avoided all but the most timid pronouncements on the bloodletting and corruption – something observers attribute to the Catholic hierarchy’s gradual rapprochement with the political class.  Politicians seem anxious to appear with the pope, too, suggesting that the political class needs the church to bolster its popular appeal amid a string of scandals and desperately low popularity ratings.  “The government will try to legitimize itself with [the pope’s] visit,” said Bernardo Barranco, a columnist and church observer.  Related: Mexico Catholic church accused of bending marriage rules for president  President Enrique Peña Nieto and first lady Angélica Rivera, whose marriage was allegedly facilitated by the church fast-tracking an annulment for Rivera, will welcome Pope Francis as he arrives in Mexico City on Friday.  It would have been an unthinkable act a generation earlier.  Observers suspect the visit may prove problematic for politicians in search of approval and prelates seen as seeking a spot at the right hand of power, however.  “[The pope] is deeply frustrated with what is happening in Mexico for a simple reason: what’s happening in Mexico involves Catholics,” said Semo, the political historian. “Those who are dying, those who are working with the narcos – these are Catholics.”
Pope Francis’s visit is expected to unsettle the complex relationship between church and politics that manifests in a unique expression of popular Catholicism