The name of the villa does not come from _castle_ as is often said, but from the roman _castellum_, a receptacle for water. Villani tells us that Marcrinus, a Roman senator, made a conduit on arches and brought the water seven miles, in order that the citizens of Florentia might have abundance of good water to drink. The aqueduct started from the streamlet Marina at the foot of Monte Morello, and collected all the springs above Sesto, Quinto, Colonnato, etc., on its way. That worthy old academician, Domenico Manni, in his book _Le Terme Fiorentine_, describes various arches, pilasters, and great pieces of masonry still existing in his time (1750) near Doccia, near the torrent Mugnone, near the Villa Corsini, close to Castello, and at Ponte a Rifredi. He gives drawings of two arches which soon afterwards fell down, and copies of many inscriptions found while digging foundations for houses or ploughing the fields. The aqueduct is still commemorated in the name of a church near Montughi, San Stefano in Pane de Arcora. Caterina Sforza, widow of Giovanni de’ Medici, the celebrated mother of a still more celebrated son, inhabited Castello during the last seven years of her chequered existence. An illegitimate daughter of the Duke of Milan, she was affianced at eleven years of age to Girolamo Riario, a favourite nephew of Sixtus, and married to him after the murder of her father. Her beauty, grace of manner, wit and intelligence gained the heart, not only of the Pope but of all who knew her, to judge by the impassioned description given by Fabio Oliva when she was about twenty. “As she issued from her litter, it seemed as if the sun had emerged, so gorgeously beautiful did she appear, laden with silver and gold and jewels, but still more striking from her natural charms. Her hair, wreathed in the manner of a coronet, was brighter than the gold with which it was entwined. Her forehead of burnished ivory almost reflected the beholders. Her eyes sparkled behind the mantling crimson of her cheeks, as morning stars amid those many-tinted lilies which returning dawn scatters along the horizon.” After the murder of her first husband in 1488, avenged by her without mercy, she proclaimed her son Ottaviano, Count of Forli; and soon afterwards married Giacomo Fea, the handsome, loyal and brave captain who kept the citadel of Forli so well against the insurgents who had killed Count Girolamo Riario. Ratti, the biographer of the Sforzas says: “It would be difficult to find in history any woman who so far surpassed her sex, who was so much the amazement of her contemporaries and the marvel of posterity. Endowed with a lofty and masculine spirit, she was born to command; great in peace, valiant in war, beloved by her subjects, dreaded by her foes, admired by foreigners.” Likenesses of Caterina, of her first husband and her two eldest sons, are to be seen in the altarpiece of the Torelli chapel in the church of San Girolamo at Forli.