PIACENZA (Lat. Placentia), a town and episcopal see of Emilia, Italy, the capital of the province of Piacenza, 42½ m. S.E. of Milan and 91 m. N.W. of Bologna by rail. Pop. (1906), 39,786. It lies on the Lombard plain, 217 ft. above sea-level, near the right bank of the Po, which here is crossed by road and railway bridges, just below the confluence of the Trebia. It is still surrounded by walls with bastions and fosse in a circuit of 4 m. The cathedral was erected between 1122 and 1233, in the Lombard Romanesque style, under the direction of Santo da Sambuceto, on the site of a church of the 9th century which had been destroyed by earthquake. The west front has three doors with curious pillared porches. The campanile is a massive square brick tower 223 ft. high; the iron cage attached to one of its windows was put up in 1495 by Ludovico il Moro for the confinement of persons guilty of treason or sacrilege. The crypt is a large church supported by one hundred columns. The entire edifice has been restored since 1898, and the frescoes by Guercino and Caracci, which decorate parts of its roof, though good in themselves, are inappropriate to its severe style. Sant' Antonino, which was the cathedral church till 877, is supposed to have been founded by St Victor, the first bishop of Piacenza, in the 4th century, and restored in 903; it was rebuilt in 1104, and altered in 1857. It was within its walls that the deputies of the Lombard League swore to the conditions of peace ratified in 1183 at Constance. The Gothic brick vestibule (Il Paradiso) on the north side is one of the older parts of the building. San Francesco, a spacious Gothic edifice begun by the Franciscans in 1278, was erected on the site of the palace of Ubertino Landi, a leader of the Ghibelline party. S. Savino, a fine Romanesque building of A.D. 903 (well restored in 1903), contains a mosaic pavement of this period with curious representations, including one of a game of chess. S. Sisto, which dates from 1499, and takes the place of the church founded in 874 by Angilberga (consort of the emperor Louis II.), lost its chief attraction when Raphael's Sistine Madonna (now in Dresden) was sold by the monks in 1754 to Frederick Augustus III. Its place, however, is occupied by a copy by Avanzini, and there are also several good intarsias by Bartolomeo da Busseto. S. Sepolcro and S. Maria della Campagna are both good early Renaissance churches; the latter is rich in frescoes by Pordenone. S. Anna, dating from 1334, was the church of the barefooted Carmelites. Of the secular buildings the most interesting is the Palazzo Communale, begun in 1281, one of the finest buildings of its kind in Italy. The square in front is known as the Piazza dei Cavalli, from the two bronze equestrian statues of Ranuccio (1620) and his father Alexander, prince of Parma, governor of the Netherlands (1625). Both were designed by Francesco Mocchi. The Palazzo dei Tribunali and the Palazzo degli Scoti are fine early Renaissance brick buildings with terra-cotta decorations. The huge Farnese palace was begun after Vignola's designs by Margaret of Austria in 1558, but it was never completed, and since 1800 it has been used as barracks. Other buildings or institutions of note are the old and the new bishop's palace, the fine theatre designed by Lotario Tomba in 1803, the great hospital dating from 1471, the library presented to the commune in 1846 by the marquis Ferdinando Landi, and the Passerini library founded in 1685. The Museo Civico, formed in 1903, contains collections of antiquities (though many of the Roman antiquities of Piacenza have passed to the museum of Parma), some good Flemish tapestries and a few pictures. The castle erected by Antonio da Sangallo the younger has been demolished. Piacenza is the junction of the Milan and Bologna line with that from Voghera and Turin. From Codogno, 7 m. to the north, a branch line runs to Cremona. By road Piacenza is 88 m. north-east of Genoa. The town has an arsenal, a technical and arts school, and various industries—iron and brass works, foundries, silk-throwing, printing works and flour mills.
Piacenza was made a Roman colony in 218 B.C. While its walls were yet unfinished it had to repulse an attack by the Gauls, and in the latter part of 218 it afforded protection to the remains of the Roman army under Scipio which had been defeated in the great battle on the Trebia. In 205 it withstood a protracted siege by Hasdrubal. Five years later the Gauls burned the city; and in 190 it had to be recruited with three thousand families. In 187 it was connected with Ariminum and the south by the construction of the Via Aemilia. Later on it became a very important road centre; the continuation northwards of the Via Aemilia towards Milan, with a branch to Ticinum, crossed the Po there, and the Via Postumia from Cremona to Dertona and Genoa passed through it. Later still Augustus reconstructed the road from Dertona to Vade, and into Gallia Narbonensis, and gave it the name of Tulia Augusta from Placentia onwards. The rectangular arrangement of the streets in the centre of the town, through which passes the Via Aemilia, is no doubt a survival from Roman times. Placentia is mentioned in connexion with its capture by Cinna and a defeat of the forces of Carbo in the neighbourhood (82 B.C.), a mutiny of Julius Caesar's garrison (50 B.C.), another mutiny under Augustus (40 B.C.), the defence of the city by Spurinna, Otho's general, against Caecina, Vitellius's general (A.D. 69), and the defeat of Aurehan by the Marcomanni outside the walls (A.D. 271). In 546 Totila reduced Piacenza by famine. Between 997 and 1035 the city was governed by its bishops, who had received the title of count from Otho III. At Roncaglia, 5 m. to the east, the emperor Conrad II. held the diet which passed the Salic law. In the latter part of the 12th century it was one of the leading members of the Lombard League. For the most part it remained Guelph, though at times, as when it called in Galeazzo Visconti, it was glad to appeal to a powerful Ghibelline for aid against its domestic tyrants. In 1447 the city was captured and sacked by Francesco Sforza. Having been occupied by the papal forces in 1512, it was in 1545 united with Parma (q.v.) to form an hereditary duchy for Pierluigi Farnese, son of Paul III. In 1746 a battle between the Franco-Spanish forces and the Austrians was fought under the city walls, and in 1796 it was occupied by the French. In 1848 Piacenza was the first of the towns of Lombardy to join Piedmont; but it was reoccupied by the Austrians till 1859.