Antonelli, Giacomo (jä'kōmō äntōnel'lē) [key], 1806–76, Italian cardinal and statesman of the Roman Catholic Church, adviser to Pope Pius IX. He received the red hat of the cardinalate in 1847, presided over the council drafting the constitution for the Papal States, and became the premier of the pope's first constitutional cabinet. After returning (1850) from exile in Gaeta, Pius IX made him secretary of state. His vigorous diplomacy was directed against Italian national unification.
