Development as a fortress In the
Roman era, a fortified tower may have been constructed to guard the crossing of two
Roman roads that met on the territory of what is now Luxembourg City, although historian claims no structure is believed to have existed at said crossing. Some of the earliest known settlements within modern city boundaries were established by
Frankish colonizers in the
Alzette valley around what is now
Dommeldange,
Pfaffenthal and the
Grund. In 963, through an exchange treaty with the abbey of
Saint Maximin in
Trier,
Siegfried I of the
Ardennes - a close relative of
King Louis II of
France and
Emperor Otto the Great - acquired the
castellum Lucilinburhuc ("small castle"), a military structure built around the 9th or early 10th century on what is now the
Fish Market. These were then enlarged under French rule by
Marshal Vauban, and augmented again under Austrian rule in the 1730s and 1740s. During the
French Revolutionary Wars, the city was occupied by
France twice: once, briefly, in 1792–93, and, later, after a seven-month
siege. Luxembourg held out for so long under the French siege that French politician and military engineer
Lazare Carnot called Luxembourg "the best
fortress in the world, except Gibraltar", giving rise to the city's nickname: the '
Gibraltar of the North'. Nonetheless, the Austrian garrison eventually surrendered, and as a consequence, Luxembourg was annexed by the French Republic, becoming part of the
département of
Forêts, with Luxembourg City as its
préfecture. Under the 1815
Treaty of Paris, which ended the
Napoleonic Wars, Luxembourg City was placed under
Prussian military control as a part of the
German Confederation, although sovereignty passed to the
House of Orange-Nassau, in
personal union with the
United Kingdom of the Netherlands.
Transition to a modern city After the
Luxembourg Crisis, the 1867
Treaty of London required Luxembourg to dismantle the fortifications in Luxembourg City. By that time, the city had an area of , while the surrounding defensive works took up , around which a building restriction perimeter of nearly , first established by the Austrians in 1749 for security reasons, had made further urbanisation impossible. Their demolition, which would signify the opening of the city, took sixteen years, cost 1.5 million gold
francs, and required the destruction of over of underground defences and of
casemates,
batteries,
barracks, etc. over the
Pétrusse valley, also known as the viaduct or old bridge, opened in 1861. When, in 1890,
Grand Duke William III died without any male heirs, the Grand Duchy passed out of Dutch hands, and into an independent line under
Grand Duke Adolphe. Thus, Luxembourg, which had hitherto been independent in theory only, became a truly independent country, and Luxembourg City regained some of the importance that it had lost in 1867 by becoming the capital of a fully independent state. Despite Luxembourg's best efforts to remain
neutral in the First World War, it was
occupied by Germany on 2 August 1914. On 30 August,
Helmuth von Moltke moved his headquarters to Luxembourg City, closer to his armies in France in preparation for a swift victory. However, the victory never came, and Luxembourg would play host to the German high command for another four years. At the end of the occupation, Luxembourg City was the scene of an attempted
communist revolution; on 9 November 1918, communists declared a
socialist republic, but it lasted only a few hours. In 1920 and 1921, the
city limits were greatly expanded, with the communes of
Eich,
Hamm,
Hollerich, and
Rollingergrund all merging with Luxembourg City. Until then, the city proper had only had an area of ; the merger gave Luxembourg City a new area of , making the city the largest commune in the country (a position that it would hold until 1978). In 1940,
Germany occupied Luxembourg again. The
Nazis were not prepared to allow Luxembourgers self-government, and gradually integrated Luxembourg into the Third Reich by informally attaching the country administratively to a neighbouring German province. Under the occupation, the capital city's streets all received new, German names, which was announced on 4 October 1940. The Avenue de la Liberté for example, a major road leading to the railway station, was renamed "Adolf-Hitlerstraße". Luxembourg City was liberated on 10 September 1944, after which the pre-occupation city boundaries were restored. The city was under long-range bombardment by the German
V-3 cannon in December 1944 and January 1945. After the war, Luxembourg ended its neutrality, and became a founding member of several inter-governmental and supra-governmental institutions. In 1952, the city became the headquarters of the High Authority of the
European Coal and Steel Community. In 1967, the High Authority was merged with the commissions of the other European institutions; although Luxembourg City was no longer the seat of the ECSC, it hosted some part-sessions of the
European Parliament until 1981. Luxembourg remains the seat of the European Parliament's secretariat, as well as the
Court of Justice of the European Union, the
European Court of Auditors, and the
European Investment Bank. Several departments of the
European Commission are also based in Luxembourg. The
Council of the EU meets in the city for the months of April, June and October annually. ==Geography==