but the expulsion of the
Jews in 1414, and still more the exclusion, under Jesuit influence, of
Protestants from the right to acquire citizenship, and from the
magistracy, dealt severe blows at the prosperity of the place. A variety
of other causes contributed to its decay: the opening up of new trade
routes, the gradual ossification of the gilds into close and corrupt
corporations, above all the wars in the Netherlands, the Thirty Years'
War, and the Wars of the Spanish and Austrian Succession. When in 1794
Cologne was occupied by the French, it was a poor and decayed city of
some 40,000 inhabitants, of whom only 6000 possessed civic rights. When,
in 1801, by the treaty of Luneville, it was incorporated in France, it
was not important enough to be more than the chief town of an
arrondissement. On the death of the last elector in 1801 the
archiepiscopal see was left vacant. With the assignment of the city to
Prussia by the congress of Vienna in 1815 a new era of prosperity began.
The university, indeed, was definitively established at Bonn, but the
archbishopric was restored (1821) as part of the new ecclesiastical
organization of Prussia, and the city became the seat of the president
of a governmental district. Its prosperity now rapidly increased; when
railways were introduced it became the meeting-place of several lines,
and in 1881 its growth necessitated the pushing outward of the circle of
fortifications.

See L. Ennen, _Gesch. der Stadt Koln_ (5 vols., Cologne, 1863-1880) to
1648, and _Frankreich und der Niederrhein_ (2 vols., ib., 1855, 1856),
a history of the city and electorate of Cologne since the Thirty
Years' War; R. Schultze and C. Steuernagel, _Colonia Agrippinensis_
(Bonn, 1895); K. Heldmann, _Der Kolngau und die Civitas Koln_ (Halle,
1900); L. Korth, _Koln im Mittelalter_ (Cologne, 1890); F. Lau,
_Entwickelung der kommunalen Verfassung der Stadt Koln bis zum Jahre
1396_ (Bonn, 1898); K. Hegel, _Stadte und Gilden der germanischen
Volker im Mittelalter_ (2 vols., Leipzig, 1891), ii. p. 323; H.
Keussen, _Historische Topographie der Stadt Koln im Mittelalter_
(Bonn, 1906); W. Behnke, _Aus Kolns Franzosenzeit_ (Cologne, 1901);
Helmken, _Koln und seine Sehenswurdigkeiten_ (20th ed., Cologne,
1903). For sources see L. Ennen and G. Eckertz, _Quellen zur
Geschichte der Stadt Koln_ (6 vols., Cologne, 1860-1879); later
sources will be found in U. Chevalier, _Repertoire des sources his