GIGLIO (anc. Igilium), an island of Italy, off the S.W. coast of Italy, in the province of Grosseto, 11 m. to the W. of Monte Argentario, the nearest point on the coast. It measures about 5 m. by 3 and its highest point is 1634 ft. above sea-level. Pop. (1901) 2062. It is partly composed of granite, which was quarried here by the Romans, and is still used; the island is fertile, and produces wine and fruit, the cultivation of which has taken the place of the forests of which Rutilius spoke (Itin. i. 325, “eminus Igilii silvosa cacumina miror”). Julius Caesar mentions its sailors in the fleet of Domitius Ahenobarbus. In Rutilius’s time it served as a place of refuge from the barbarian invaders. Charlemagne gave it to the abbey of Tre Fontane at Rome. In the 14th century it belonged to Pisa, then to Florence, then, after being seized by the Spanish fleet, it was ceded to Antonio Piccolomini, nephew of Pius II. In 1558 it was sold to the wife of Cosimo I. of Florence.
See Archduke Ludwig Salvator, Die Insel Giglio (Prague, 1900).