The Duchy of Luxemburg (; ; ; ) was a state of the Holy Roman Empire, the ancestral homeland of the noble House of Luxembourg. The House of Luxembourg, now Duke of Limburg, became one of the most important political forces in the 14th century, competing against the House of Habsburg for supremacy in Central Europe. They would be the heirs to the Přemyslid dynasty in the Kingdom of Bohemia, succeeding the Kingdom of Hungary and contributing four Holy Roman Emperors until their own line of male heirs came to an end and the House of Habsburg got the pieces that the two Houses had originally agreed upon in the Treaty of Brünn in 1364.
In 1443, the duchy passed to Duke Philip the Good of Burgundy of the French House of Valois, and, in 1477, by marriage to Archduke Maximilian I of Austria of the House of Habsburg. The Seventeen Provinces of the former Burgundian Netherlands were formed into an integral union by Holy Roman Emperor Charles V in the Pragmatic Sanction of 1549. In 1795, French revolutionaries ended this situation.
Pre-Duchy
The first known reference to the territory was made by Julius Caesar in his Commentaries on the Gallic War. The historical region of Luxembourg belonged to the Roman province of Belgica Prima. After the invasion of the Germanic tribes from the East, Luxembourg became part of the Frankish Empire. By the 843 Treaty of Verdun, it became part of the Lotharingian province of Middle Francia. According to the Treaty of Ribemont in 880, it had finally fallen to East Francia.
Modern historians explain the etymology of the word Luxembourg as coming from the word Letze, meaning fortification, which might have referred to either the remains of a Roman watchtower or a primitive refuge of the Early Middle Ages.
Proto-Duchy (963–1353)
By the 959 partition of Lotharingia, the Luxembourg region had passed to Duke Frederick I of Upper Lorraine of the House of Ardenne–Bar, a son of Count Palatine Wigeric of Lotharingia. In 963, Count Siegfried, probably a younger brother of Duke Frederick I, purchased some land from Abbot Wikerus of Saint Maximin's in Trier. This land was centered on a ruined (supposedly Roman) fort by the Old High German name of Lucilinburhuc (commonly translated as "little castle"). In the following years, Count Siegfried had a new castle built on the site of these ruins, on a rock that would later be called Bock Fiels. This castle dominated a stretch of the old Roman road linking Reims, Arlon, and Trier, and opened some prospects for trade and taxation. Despite this new construction, it seems that Siegfried and his immediate successors did not make the castle their primary residence. The history of Luxembourg proper began with the construction of this castle.
In the following years, a small town and market grew around the new castle. The first inhabitants were probably servants of Count Siegfried and clergy of Saint Michael's church. This settlement soon received additional protection by the construction of a first, partial city wall and moat.
In addition to the small town near Bock Fiels and the Roman road, another settlement was formed in the Alzette Valley (today the Grund quarter). By 1083, this lower town contained two churches, two bridges of the rivers Alzette, and Petruss. Its inhabitants pursued various professions, including fishing, baking and milling. That same year, the Benedictine abbey of Altmünster was founded by Count Conrad on the hill behind Luxembourg castle.
Henry III was the first count known to have established his permanent residence in Luxembourg castle. In a document from the year 1089, he is referred to as comes Henricus de Lutzeleburg, which also makes him the first documented count of Luxembourg.
Around this fort, the town gradually developed and became the center of a small, but important state of great strategic value to France, Germany, and the Low Countries. Luxembourg's fortress was steadily enlarged and strengthened over the years by successive owners, making the Fortress of Luxembourg one of the strongest in continental Europe. Its formidable defenses and strategic location caused it to become known as the Gibraltar of the North.
The House of Luxembourg provided several Holy Roman Emperors, kings of Bohemia, and archbishops of Trier and Mainz. From the Early Middle Ages to the Renaissance, Luxembourg bore multiple names, including Lucilinburhuc, Lutzburg, Lützelburg, Luccelemburc, and Lichtburg, among others.
The Duchy (1353–1797)