Triptych with polychrome mosaics of Murano in the tower of the Palazzo Pubblico show, from left to right:
San Leo di Montefeltro / St. Leo of Montefeltro (c. 275-366), stonecutter from Dalmatia, companion of St. Marinus; bishop of Montefeltro, founded the town of San Leo (Wikipedia).
San Marino / St. Marinus (Rab c. 275 - Città di San Marino 366),
stonemason, founded in 301 a chapel and monastery on Mt. Titano, from where the republic of San Marino grew (Wikipedia).
Sant'Agata / St. Agatha of Sicily (231-251), virgin martyr, patron saint of San Marino (Wikipedia).