Passau a picturesque fortified frontier town of Bavaria, containing 15,583 people, and situated at the confluence of the Inn and the Ilz with the Danube, ninety miles east-north-east of Munich, and rising like an amphitheatre on the most beautiful spot of the Danube, is strikingly effective and picturesque. The place is especially celebrated in Protestant Church history, for it was here that the treaty of Passau was signed Aug. 2, 1552, by the emperor Charles V on the one side and the Protestant princes of Germany on the other, giving public recognition to the Lutheran faith as among the ecclesiastical institutions of the empire. Among the chief buildings are the cathedral, the bishop's palace, the post-office (where the treaty of Passau was signed in 1552); the Jesuits' College, a large building now used as at school; and the church of St. Michael's. In the Cathedral Square (Domplatz) is a bronze statue of king Maximilian Joseph, of recent erection. Passau contains also numerous picture-galleries, collections of antiquities, and benevolent and charitable institutions. The natural advantages of this site, in a military point of view, were appreciated at an early period by the Romans, who erected a strong camp here, garrisoned it with Batavian troops, and from this circumstance named it Batava Castra. Passau was long the seat of a bishopric founded in the 7th century, but secularized in 1803. The cathedral of Passau and great part of the town were. consumed by fire in 1662. During the Reformation period many advocates of the new cause flourished in Passau, but the Jesuits of Vienna, who in 1612 succeeded in establishing a college at Passau, used all means at their command to reinstate Romanism at this place in its wonted glory and power, and they succeeded so well that the Protestant fold has been reduced to a mere trifle. See Spieker, Gesch. des Augsburger Religions friedens (Schlitz, 1854); Ranke, Reformationsgesch. vol. vii; Soames, Hist. of the Ref 3:747; Hefele, Conciliengesch. v. 26 sq.; Fisher, Hist. of the Ref. p. 167; Gieseler, Eccles. Hist. 4:206. SEE PROTESTANTISM; SEE REFORMATION.