The San Marcos Fair has a religious component, since it is celebrated in honor of San Marcos, patron saint of the city of Aguascalientes. That is why the most important day of the FNSM is April 25, the day of the patron saint, and begins with the traditional Mañanitas in the Garden of San Marcos by the Municipal Symphonic Band, after which there is a Misa de Gallo in the same temple.