This day (English: Anniversary of the Constitution) commemorates the Constitution of 1917, promulgated after the Mexican Revolution on February 5. Article 74 of the Mexican labor law (Ley Federal del Trabajo) provides that the first Monday of February (regardless the date) will be an official holiday in Mexico. This was a modification of the law made in 2005, effective since 2006; before, it was the February 5th regardless of the day.