Cinco de Mayo (Spanish for “May fifth”) is a relatively minor Mexican holiday commemorating the Battle of Puebla of May 5, 1862, in which Mexican forces defeated an invading French army far superior in numbers and equipment. Mexico only temporarily halted the French invasion; French reinforcements soon conquered the capital and it was not until 1867 that Mexico finally freed itself from French control.
However, Cinco de Mayo has taken on a life of its own in the United States, celebrated by Mexican-Americans and many others. Some parishes with significant Mexican populations participate in civic or community activities to celebrate the holiday. Any national or cultural holiday is a good occasion to pray for one’s country or cultural group. But in itself Cinco de Mayo has no more intrinsic religious significance than Independence Day, Flag Day or any other civic holiday.