Liège is situated at the confluence of the Meuse which, at the city, flows through a deep ravine and the Ourthe, between the Ardennes to the south and Maastricht (in the Netherlands) and Flanders to the north and west. The city lies on the main rail lines from Germany to Brussels and Paris, which Schlieffen and Moltke planned to use in an invasion of France. Much industrial development had taken place in Liège and the vicinity, which presented an obstacle to an invading force. The main defences were a ring of twelve forts 6 – from the city, built in 1892 by Henri Alexis Brialmont, the leading fortress engineer of the nineteenth century. The forts were sited about 4 km apart to be mutually supporting but had been designed for frontal, rather than all-round defence.
18th century philosophers were far from unanimous in their opinion of the Principality of Liège. Some saw in the functioning of its state all the characteristics of a republic, while others saw the bishop's power as that of a tyrant. The chevalier de Jaucourt's account of Liège in the Encyclopédie states: [Here there are] 32 artisans' colleges, who take some part in the government, and bear the ease of the city. [The Liège state shows itself] as a free republic, governed by mayors, by its senators and by other municipal magistrates. [Nevertheless] its number of churches, abbeys and monasteries considerably oppress it. On the other side, Voltaire's criticism of Liège's government was sharp, writing in the Idée républicaines par un membre d’un corps, critique du Contrat social about Notker of Liège, the principality's founder : It is an insult to reason and law to pronounce the words "civil and ecclesiastical government". When our bishop, made to serve not to be served, made to support the poor not devour their livelihood, made to catechise and not to dominate, ventures, in times of anarchy, is entitled the prince of the city of which he is not the pastor, he is manifestly culpable of rebellion and tyranny.
The next day, Liège surrendered, and at the command of Charles the Bold, hundreds of Liègois were tied together and thrown into the Meuse river. The city was set alight and is said to have burned for seven weeks.
The unrest in Liège did not abate. In 1466, the city of Dinant, to the south-west, rebelled and Philip the Good again sent troops, commanded by Charles the Bold, who punished the city by casting 800 burghers into the river Meuse and burnt the city.
Vincent de Bueren organised the defence of the city of Liège and achieved some successes with hit-and-run sorties. Jean de Wilde was mortally wounded during the raid of 26 October and died two days later. Best known is the attack by the six hundred Franchimontois in the night of 29–30 October, who sneaked out of the city and attacked the sleeping Burgundians, with the aim of killing the Duke and the King. The plan failed and all 600, including Vincent de Bueren and Gosuin de Streel, were killed.
In the Battle of Liège the Liège fortifications fulfilled their role, stopping the German army long enough to allow the Belgian and French armies to mobilize. The battle revealed shortcomings in the performance of the forts and in the Belgian strategy. The forts themselves suffered from inherent weakness of construction through poor understanding of concrete technology, as well as overall inadequate protection for the garrison and ammunition stores from heavy-caliber artillery bombardment. Unbreathable air from bombardment, the fort's own gun gases and from human waste compelled the surrender of most of the positions. However, the days-long delay caused by the fortress ring allowed the Belgian, and more importantly, the French armies to complete their mobilizations. Had the Germans captured Liège as they had hoped, by a bold stroke, the German army could have been in Paris before France could organize its defence at the First Battle of the Marne.
One night, a Liège militia attacked Tongeren and killed all Burgundians there. After this, Jean de Wilde opened negotiations with Guy of Humbercourt. But Charles the Bold had other plans: he led an army towards Liège to deal once and for all with the rebellious city. He was accompanied by Louis XI of France. Several cities on their path were plundered, including Tongeren.
After the battle, Charles moved on Liège and forced the city to surrender on 12 November. The Prince-Bishopric became a Burgundian protectorate under Guy of Humbercourt, and all cities in the County of Loon were forced to tear down their defences.
When Philip died in 1467, unrest broke out in the city of Liège and Louis of Bourbon was forced to flee to Huy, to the west. Even there, his position was not secure and he was forced to flee the Prince-Bishopric together with all the Burgundians. Again, Raes van Heers and Count Jan de Wilde of Kessenich raised an army to confront Charles the Bold. The reinforcements promised by Louis XI of France again didn't materialise, and the troops of Liège were decisively defeated in the Battle of Brustem on 28 October 1467.
Philip the Good sent an army, under command of his son Charles the Bold, to Liège to restore his authority. Raes van Heers assembled an army of 4,000 men, mostly civilians and confronted Charles the Bold at the Battle of Montenaken on 20 October 1465. The battle was a clear victory for the Burgundians. Burgundian forces went on to occupy Sint-Truiden, where the Peace of Sint-Truiden was signed. Under the terms of the agreement, Liège lost all its rights and Louis of Bourbon was reinstated as Prince-Bishop.
Still, the people of Liège refused to accept Burgundian rule. In October 1468, 240 rebels, under Jean de Wilde, Vincent de Bueren and Gosuin de Streel, invaded the city. In the confusion, Guy of Humbercourt and the entire Burgundian garrison fled. Liège was free again and Jean de Wilde occupied the Prince-Bishops' palace.
In 1762, the Jesuits were formally expelled from France, beginning the college's decline and eventual end. The expulsion split the college. The Jesuit faculty and many of the students fled to the Austrian Netherlands (now part of modern Belgium), moving first to Bruges, and then operating under the protection of the Bishop of Liège from 1773. King Louis XV continued the college at St. Omer, under the direction of secular clergy. When the Jesuit order was suppressed everywhere in 1773, this dual system ended, but the college never regained its prominence. In 1793, the French Revolution and the United Kingdom's declaration of war on France ended the Saint Omer college. The English faculty and students were imprisoned until February 1795. English penal laws and related discrimination had changed regarding Catholic education, so when released, some of the staff and most of the then about 100 students went to England, in order to avoid war on the European continent. A former student, Thomas Weld, donated a mansion and grounds at Stonyhurst, in Lancashire. The modern school, Stonyhurst College continues to this day as a direct lineal descendant of the College of Saint-Omer. The Lycée Alexandre Ribot now stands on the site of the former college in Saint Omer.
The city of Liège is still developing the concept, where the University of Liège's student union started developing 4 KàPs.
RFC Liège won the first-ever Belgian title in 1896. The club struggled financially during the early years of the 21st century and was eventually dissolved in 2011. A new club was formed, which is currently competing in the First Amateur Division.
In 1990 the Pesant Club Liégeois partnered with the Société du Tour de France, the organizer of cycling's flagships the Tour de France and Paris–Roubaix. The partnership led to a more professional organization, resulting in a complete overhauling of the race course: the start and finish moved to different locations in Liège and five new climbs were included.
To make the event even tougher for the tiny cars and their drivers, it was run almost non-stop. The cars left Liège at 17.30 on Thursday, July 17, 1958 and drove in convoy to Spa. There they lined up to start from 21.00 that evening. They would not rest until Saturday morning, when they were due to arrive in Brescia, Italy (having driven 1970 km via Ljubljana in Slovenia) at 09.50. The cars went into parc ferme and could not be touched for eight hours. From 18.00, the cars left the Piazza Loggia in Brescia to drive back over the Gavia and Stelvio, through Austria, up the German autobahn and back to arrive at Spa, a claimed total distance of 3203 km, at 16.47 on Sunday.
Since the finish returned to Liège in 2019, the Côte de Saint-Nicolas has been removed from the route, and the decisive climbs are once again the Côte de la Redoute, Côte des Forges and Côte de la Roche-aux-Faucons.
The Liège municipality (i.e. the city proper) includes the former communes of Angleur, Bressoux, Chênée, Glain, Grivegnée, Jupille-sur-Meuse, Rocourt, and Wandre. In November 2012, Liège had 198,280 inhabitants. The metropolitan area, including the outer commuter zone, covers an area of 1,879 km 2 (725 sq mi) and had a total population of 749,110 on 1 January 2008. This includes a total of 52 municipalities, among others, Herstal and Seraing. Liège ranks as the third most populous urban area in Belgium, after Brussels and Antwerp, and the fourth municipality after Antwerp, Ghent and Charleroi.
Liège began to suffer from a relative decline of its industry, particularly the coal industry, and later the steel industry, producing high levels of unemployment and stoking social tension. During the 1960-1961 Winter General Strike, disgruntled workers went on a rampage and severely damaged the central railway station Guillemins. The unrest was so intense that "army troops had to wade through caltrops, trees, concrete blocks, car and crane wrecks to advance. Streets were dug up. Liège saw the worst fighting on 6 January 1961. In all, 75 people were injured during seven hours of street battles."
Although settlements already existed in Roman times, the first references to Liège are from 558, when it was known as Vicus Leudicus. Around 705, Saint Lambert of Maastricht is credited with completing the Christianization of the region, indicating that up to the early 8th century the religious practices of antiquity had survived in some form. Christian conversion may still not have been quite universal, since Lambert was murdered in Liège and thereafter regarded as a martyr for his faith. To enshrine St. Lambert's relics, his successor, Hubertus (later to become St. Hubert), built a basilica near the bishop's residence which became the true nucleus of the city. A few centuries later, the city became the capital of a prince-bishopric, which lasted from 985 till 1794. The first prince-bishop, Notger, transformed the city into a major intellectual and ecclesiastical centre, which maintained its cultural importance during the Middle Ages. Pope Clement VI recruited several musicians from Liège to perform in the Papal court at Avignon, thereby sanctioning the practice of polyphony in the religious realm. The city was renowned for its many churches, the oldest of which, St Martin's, dates from 682. Although nominally part of the Holy Roman Empire, in practice it possessed a large degree of independence.