A triduum in honour of the saint and a solemn Mass at the Monastery with the procession through the streets of the town. On September 19 the celebrations of San Marco Papa take place with religious rites, the popular feast and the fair. The latter is an old tradition which started at the end of the 17th, when the Emperor Guido in the year 892 gave permission for an annual market to be held, which was called "Sabbatino", because it took place on the third Saturday in September: from the mercato Sabbatino it has transformed into "La fiera", a fixed date which coincides with the feast of the patron saint, and to joyfully conclude the celebrations, a fireworks display illuminates the sports field and the surrounding area. 

Sources: monte-amiata.eu ; comune.abbadia.siena.it