Appiano, the name of an Italian family which ruled over Pisa and Piombino from the 14th to the 17th century. I. Jacopo I., the founder of the family, died Sept. 5, 1398. Having attached himself to the Ghibelline party, he conspired with Galeazzo Visconti, sovereign of Milan, excited in 1392 a commotion in the streets of Pisa, during which he effected the massacre of the chief magistrate, Pietro Gambacorti, and his two sons, and in the midst of the popular consternation assumed the title of sovereign of Pisa.

II. Gherardo, son and successor of the preceding, sold Pisa to Visconti, duke of Milan, for 200,000 florins, reserving to himself only the sovereignty of Piombino and the isle of Elba, whither he withdrew in 1399. His descendants of the male line preserved for two centuries the principality of Piombino, after which it was surrendered in 1031 by the emperor Ferdinand II. to Philip IV. of Spain.

III. Jacopo III., ruler of Piombino, died in 1474. A conspiracy against him, aided by Galeazzo Maria Sforza, duke of Milan, proved unsuccessful, but Jacopo was obliged to place himself under the protection of Ferdinand, king of Naples. He consented to receive a Neapolitan garrison in Piombino, and in return was permitted to join to his own name that of Aragona.

IV. Jacopo IV., son of the preceding, sovereign of Piombino, died in 1511. He married a daughter of the king of Naples, and took a command in the army directed by that princo and by Sixtus IV. against Lorenzo de' Medici. He was taken prisoner by the Florentines and obliged to pay a ransom for his liberty. In 1501 CAesar Borgia took possession of Piombino, but Jacopo was restored by an insurrection of the people.