SENIGALLIA, or SINIGAGLIA (anc. Sena Gallica)  , a city and episcopal see of the Marches, Italy, in the province of Ancona, on the coast of the Adriatic, 15 M. by rail N. of Ancona . Pop . (1901) 5556 (town), 23,195 (commune) . It is situated at 14 ft. above sea-level, and, despite its ancient origin, presents a modern appearance, with wide streets . The Palazzo Comunale dates from the 17th century . The cathedral was erected after 1787 . The castle, ,of Gothic origin, was restored by Baccio Pontelli, a famous military architect, in 1492 . The church of S Maria delle Grazie outside the town is one of the only two churches which he is known to have executed (the other is at Orciano near Mondavio, about 15 M. to the west by road) . The small port is formed by the lower reaches of the Misa, a stream which flows through the town between embankments constructed of Istrian marble . The inhabitants are chiefly occupied in fishing, and in the summer the town is greatly frequented by visitors for the good sea-bathing . Senigallia used to hold one of the largest fairs in Italy, which dated originally from 1200, when Sergius, count of Senigallia, received from the count of Marseilles, to whose daughter he was affianced, certain relics of Mary Magdalene; this fair used to be visited by merchants from France, Switzerland, Austria, Germany and especially the Levant . Senigallia is the residence of the Mastai-Ferretti family; the house in which Pope Pius IX. was born is preserved, and contains a few memorials of him .

The ancient Sena Gallica was a city of

Umbria . A colony was founded there by the Romans after their victory over the Senones, rather before 28o n.c . The place is also mentioned in connexion with Hasdrubal's defeat at the Metaurus (q.v.) in 207 B.c . It was destroyed by Pompey in 82 B.C., and is not often mentioned afterwards . No ancient remains avid very few inscriptions exist . The name Gallica distinguishes it from Saena (Siena) in Etruria . Ravaged by Alaric, fortified by the exarch Longinus, and again laid waste by the Lombards in the 8th century and by the Saracens in the 9th, Senigallia was at length brought so low by the Guelph and Ghibelline wars, and especially by the severities of Guido de Montefeltro, that it was chosen by Dante as the typical instance of . a ruined city . In the 15th century it was captured and recaptured again and again by the Malatesta and their opponents . Sigismondo Malatesta of Rimini erected strong fortifications round the town in 1450-1455 . The lordship of Senigallia was bestowed by Pius II. on his nephew Antonio Piccolomini, but the people of the town in 1464 placed themselves anew under Paul II., and Giacomo Piccolomini in 1472 failed in his attempt to seize the place . Sixtus IV. assigned the lordship to the Della Rovere family, from whom it was transferred to Lorenzo de' Medici in 1516 . After 1624 it formed part of the legation of Urbino .