PIACENZA (Lat. Placentia), a town and episcopal see of Emilia, Italy, the capital of the province of Piacenza, 424 m. S.E. of Milan and 91 m. N.W. of Bologna by rail. Pop. (1931) 46,710 (town), (commune). It lies on the Lombard plain, 217 ft. above sea-level, near the Po, which here is crossed by road and railway bridges each about 600 yd. long, just below the confluence of the Trebia. It is still surrounded by walls with bastions and fosse in a circuit of 4 miles. The cathedral was erected between 1122 and 1233, in the Lombard Romanesque style. The campanile is 223 ft. high. The entire edifice has been restored since 1898, and the frescoes by Guercino, Lodovico Caracci and Procaccini seem inappropriate to its severe style. In Sant' Antonino the deputies of the Lombard League swore to the conditions of peace ratified in 1183 at Constance. San Fran cesco is a Gothic edifice begun by the Franciscans in 1278. S. Savino, a Romanesque building of A.D. 9o3 (rebuilt in 1107 and restored in 1903) contains a mosaic pavement with curious rep resentations, including one of a game of chess. S. Sisto once contained Raphael's Sistine Madonna, now in Dresden, sold in 1754 to Frederick Augustus III. Its place is occupied by a copy by Avanzini, and there are also several good intarsias by Bartolomeo da Busseto. Of the secular buildings the most interesting is the Palazzo Comunale, begun in 1281, built in marble and brick, with beautiful windows, one of the finest buildings of its kind in Italy. The Palazzo dei Tribunali and the Palazzo degli Scoti are 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 180o it has been used as bar racks. The town has a motor car factory. It is an important
agricultural centre. Petroleum wells have been bored hereabouts.
Piacenza was made a Roman colony in 218 B.C., in which year it afforded protection to the remains of the Roman army after the battle of the Trebia (q.v.). In 205 it withstood a siege by Has drubal. Five years later the Gauls burned it; and in 190 it was recruited with 3,00o 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 continua tion 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 Vada, and into Gallia Narbonensis, and gave it the name of Julia Augusta from Placentia onwards. The rectangular arrangement of the streets in the centre of the town, through which passes the Via Aemilia, is a survival from Roman times. Placentia is mentioned fre quently as an important military point in Roman times. It was one of the leading members of the Lombard League. 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, nephew of Paul III. In 1796 it was occupied by the French. In 1848 Piacenza was the first town of Lombardy to join Piedmont, but was reoccupied by the Austrians till 1859.