Father Mateo "Elías del Socorro" Nieves Castillo relocated to a mountain hillside where he administered the Sacraments to his parishioners during the night, so federal soldiers would not find him conducting Catholic activities deemed illegal by the Mexican Socialist regime.
This was during the Cristero War (1926–29), the civil revolt by the Cristeros (Soldiers of Christ), who fought against the anti-Catholic policies pushed by Plutarco Elías Calles, who enforced the anti-clerical articles of the Mexican Constitution of 1917, which sought to eliminate the power of the Catholic Church through persecution and execution.
Countless faithful were martyred and 4,000 priests, marked as enemies of the State, were martyred in or exiled from Mexico for offering the outlawed holy sacrifice of the Mass.
Eventually, Father Mateo "Elías del Socorro" Nieves Castillo was discovered in his mountainous religious retreat, arrested and executed by gunshot on the side of the road.
"Long live Christ the King!" were his final words, on March 10, 1928.