The Four Crowned Saints is a complex of buildings located in the roman Celio district. The building occupies, from the fourth century, aristocratic late antiquity places along the Via Tuscolana. The four titular Saints are: Castorio, Sinfroniano, Claudio e Nicostrato. Legend has four marble-Christians put to death by Diocletian for having carved pagan idols. In the Middle Ages, the martyrs stonecutters became patrons of the arts and building walls corporations. The site looks like a fortified monastery (today Augustinian Convent), consists of a Basilica and a number of other areas (crypt, patios, convent, former cardinal's palace). The fortification of the complex is of the Carolingian period, attributed to Pope Leo IV. Major renovations were made to run in the fifteenth century by Cardinal Carillo, when the complex was declared Papal Vanue. Among the significant aspects: the apse that embraces all three naves, a rare example in Rome; the latest women's galleries built in the city; the St. Silvester's Oratory, decorated with remarkable thirteenth-century frescoes in Byzantine style drawn from the legend told in "Actus Silvestri"; the cycle of the Gothic frescoes, fundamental testimony of Gothic art in the city; the two chapels inside the monastery, which it is accessed from the Cloister, the St. Barbara's Oratory and the St. Nicholas's Oratory.