Sculptor and architect born in Cefalu’, Giacomo del Duca (o Jcopo Siciliano) is most remembered for assisting Michelangelo in a number of projects in Rome, including the sculpture and construction of the tomb of Pope Julius II in San Pietro in Vincoli. He also modified Michelangelo’s plans for buildings in the Capitoline Hill, one of the most famous and highest of the seven hills of Rome.
Jacopo also participated in the decoration of Porta Pia (1562) in Rome, the construction of the Palazzo Cornaro for the cardinal Alvise Cornaro, the construction of the Villa Mattei al Celio, and the completion of the nave substructure for the church of Santa Maria di Loreto (1573–1576). He also helped design the church of Santa Maria in Trivio (1575) and helped sculpt the tomb of Elena Savelli (1570) in San Giovanni in Laterano. In 1588, Del Duca returned to Sicily, and settled in Messina, where he completed a number of late mannerist structures, such as San Giovanni dei Gerolamini and the Loggia dei Mercanti.
1. Wikipedia, https://it.wikipedia.org/wiki/Giacomo_Del_Duca
2. Treccani, http://www.treccani.it/enciclopedia/giacomo-del-duca_(Dizionario-Biografico)/