He made his escape ultimately, and returned to Saxony. Arnim died suddenly at Dresden in 1641, whilst engaged in raising an army to free German soil from foreign armies of all kinds. (See THIRTY YEARS' WAR.) See K.G. Helbig, "Wallenstein und Arnim" (1850) and "Der Prager Friede," in Raumer's _Historisches Taschenbuch_ (1858); also E.D.M. Kirchner, _Das Schloss Boytzenburg, &c._ (1860) and _Archiv fur die sachsische Geschichte_, vol. viii. (1870). ARNO, ARN or AQUILA (c. 750-821), bishop and afterwards archbishop of Salzburg, entered the church at an early age, and after passing some time at Freising became abbot of Elnon, or St Amand as it was afterwards called, where he made the acquaintance of Alcuin. In 785 he was made bishop of Salzburg and in 787 was employed by Tassilo III., duke of the Bavarians, as an envoy to Charlemagne at Rome. He appears to have attracted the notice of the Frankish king, through whose influence in 798 Salzburg was made the seat of an archbishopric; and Arno, as the first holder of this office, became metropolitan of Bavaria and received the pallium from Pope Leo III. The area of his authority was extended to the east by the conquests of Charlemagne over the Avars, and he began to take a prominent part in the government of Bavaria. He acted as one of the _missi dominici_, and spent some time at the court of Charlemagne, where he was known by the assembled scholars as Aquila, and his name appears as one of the signatories to the emperor's will. He established a library at Salzburg, furthered in other ways the interests of learning, and presided over several synods called to improve the condition of the church in Bavaria. Soon after the death of Charlemagne in 814, Arno appears to have withdrawn from active life, although he retained his archbishopric until his death on the 24th of January 821. Aided by a deacon named Benedict, Arno drew up about 788 a catalogue of lands and proprietary rights belonging to the church in Bavaria, under the title of _Indiculus_ or _Congestum Arnonis_. An edition of this work, which is of considerable value to historical students, was published at Munich in 1869 with notes by F. Keinz. Many other works were produced under the protection of Arno, among them a Salzburg consuetudinary, an edition of which appears in _Quellen und Erorterungen zur bayrischen und deutschen Geschichte_, Band vii., edited by L. Rockinger (Munich, 1856). It has been suggested by W. von Giesebrecht that Arno was the author of an early section of _Annales Laurissenses majores_, which deals with the history of the Frankish kings from 741 to 829, and of which an edition appears in _Monumenta Germaniae historica. Scriptores_, Band i. pp. 128-131, edited by G.H. Pertz (Hanover, 1826). If this supposition be correct, Arno was the first extant writer to apply the name _Deutsch_ (_theodisca_) to the German language.