In memory of San Giusto, according to tradition the first evangelist of Volterra and the hills of central Tuscany, is dedicated the patronal feast of Porcari, celebrated the Monday following the Sunday of Pentecoste. The tradition involves a first Mass in the morning and a solemn celebration in the afternoon, in the presence of the citizen authority and of the original clergy of the city. The Feast ends with a procession. 

Sources: comunitapastoraleporcari.wordpress.com