Cologne ( kə-LOHN; German: Köln [kœln] ; Kölsch: Kölle [ˈkœ̂lə] ) is the fourth-most populous city of Germany and the largest city of the German state of North Rhine-Westphalia with over 1.0 million inhabitants in the city proper and over 3.1 million people in the Cologne Bonn urban region. Cologne is also part of the Rhine-Ruhr metropolitan region, the second biggest metropolitan region by GDP in the European Union. Centred on the left bank of the Rhine, Cologne is located on the River Rhine (Lower Rhine), about 35 kilometres (22 mi) southeast of the North Rhine-Westphalia state capital Düsseldorf and 22 kilometres (14 mi) northwest of Bonn, the former capital of West Germany.
The city's medieval Cologne Cathedral (Kölner Dom) was the world's tallest building from 1880 to 1890 and is today the third-tallest church and tallest cathedral in the world. It was constructed to house the Shrine of the Three Kings and is a globally recognized landmark and one of the most visited sights and pilgrimage destinations in Europe. The cityscape is further shaped by the Twelve Romanesque churches of Cologne. Cologne is famous for Eau de Cologne, which has been produced in the city since 1709; "cologne" has since come to be a generic term.
Cologne was founded in Germanic Ubii territory in the 1st century AD as the Roman Colonia Agrippina, hence its name. Agrippina was later dropped (except in Latin), and Colonia became the name of the city in its own right, which developed into modern German as Köln. Cologne, the French version of the city's name, has become standard in English as well. Cologne was the capital of the Roman province of Germania Inferior and the headquarters of the Roman military in the region until occupied by the Franks in 462. During the Middle Ages the city flourished due to its location on one of the most important trade routes between eastern and western Europe (including the Brabant Road, Via Regia and Publica). Cologne was a free imperial city of the Holy Roman Empire and a major member of the Hanseatic League. It was one of the largest European cities in medieval and renaissance times.
Prior to World War II, the city had undergone occupations by the French (1794–1815) and the British (1918–1926), and was part of Prussia beginning in 1815. Cologne was one of the most heavily bombed cities in Germany during World War II. The bombing reduced the population by 93% mainly due to evacuation, and destroyed around 80% of the millennia-old city centre. The post-war rebuilding has resulted in a mixed cityscape, restoring most major historic landmarks such as the city gates and churches (31 of them being Romanesque). The city nowadays consists of around 25% pre World War II buildings and boasts around 9,000 historic buildings.
Cologne is a major cultural centre for the Rhineland; it hosts more than 30 museums and hundreds of galleries. There are many institutions of higher education, most notably the University of Cologne, one of Germany's largest universities; the Technical University of Cologne, Germany's largest university of applied sciences; and the German Sport University Cologne. It hosts three Max Planck science institutes and is a major research hub for the aerospace industry, with the German Aerospace Center and the European Astronaut Centre headquarters. Lufthansa, Europe's largest airline, has their main corporate headquarters in Cologne. It also has a significant chemical and automobile industry. Cologne Bonn Airport is a regional hub, the main airport for the region being Düsseldorf Airport. The Cologne Trade Fair hosts a number of trade shows.
The first urban settlement on the grounds of modern-day Cologne was Oppidum Ubiorum, founded in 38 BC by the Ubii, a Cisrhenian Germanic tribe. In AD 50, the Romans founded Colonia Claudia Ara Agrippinensium (Cologne) on the river Rhine, a colonia which was named after Emperor Claudius and his wife, who was born here, Agrippina the Younger. In 85, the city became the provincial capital of Germania Inferior. It was also known as Augusta Ubiorum. Considerable Roman remains can be found in present-day Cologne, especially near the wharf area, where a 1,900-year-old Roman boat was discovered in late 2007. From 260 to 271, Cologne was the capital of the Gallic Empire under Postumus, Marius, and Victorinus. In 310, under emperor Constantine I, a bridge was built over the Rhine at Cologne. Roman imperial governors resided in the city and it became one of the most important trade and production centres in the Roman Empire north of the Alps. Cologne is shown on the 4th century Peutinger Map.
Maternus, who was elected as bishop in 313, was the first known bishop of Cologne. The city was the capital of a Roman province until it was occupied by the Ripuarian Franks in 462. Parts of the original Roman sewers are preserved underneath the city, with the new sewerage system having opened in 1890.
After the destruction of the Second Temple in the Siege of Jerusalem and the associated dispersion (diaspora) of the Jews, there is evidence of a Jewish community in Cologne. In 321, Emperor Constantine approved the settlement of a Jewish community with all the freedoms of Roman citizens. It is assumed that it was located near the Marspforte within the city wall. The Edict of Constantine to the Jews is the oldest documented evidence in Germany.
Early medieval Cologne was part of Austrasia within the Frankish Empire. Cunibert, made bishop of Cologne in 623, was an important advisor to the Merovingian King Dagobert I and served with domesticus Pepin of Landen as tutor to the king's son and heir Siegebert III, the future king of Austrasia. In 716, Charles Martel commanded an army for the first time and suffered the only defeat of his life when Chilperic II, King of Neustria, invaded Austrasia and the city fell to him in the Battle of Cologne. Charles fled to the Eifel mountains, rallied supporters and took the city back that same year after defeating Chilperic in the Battle of Amblève. Cologne had been the seat of a bishop since the Roman period; under Charlemagne, in 795, bishop Hildebold was promoted to archbishop. In the 843 Treaty of Verdun Cologne fell into the dominion of Lothair I's Middle Francia – later called Lotharingia (Lower Lorraine).
In 953, the archbishops of Cologne first gained noteworthy secular power when bishop Bruno I was appointed as duke by his brother Otto I, King of Germany. In order to weaken the secular nobility, who threatened his power, Otto endowed Bruno and his archiepiscopal successors with the prerogatives of secular princes, thus establishing the Electorate of Cologne, formed by the temporal possessions of the archbishopric and included in the end a strip of territory along the left Bank of the Rhine east of Jülich, as well as the Duchy of Westphalia on the other side of the Rhine, beyond Berg and Mark. By the end of the 12th century, the Archbishop of Cologne was one of the seven electors of the Holy Roman Emperor. Besides being prince elector, he was Archchancellor of Italy as well, technically from 1238 and permanently from 1263 until 1803.
Following the Battle of Worringen in 1288, Cologne gained its independence from the archbishops and became a Free City. Archbishop Sigfried II von Westerburg was forced to reside in Bonn. The archbishop nevertheless preserved the right of capital punishment. Thus the municipal council (though in strict political opposition towards the archbishop) depended upon him in all matters concerning criminal justice. This included torture, the sentence for which was only allowed to be handed down by the episcopal judge known as the greve. This legal situation lasted until the French conquest of Cologne.
Besides its economic and political significance Cologne also became an important centre of medieval pilgrimage, when Cologne's archbishop, Rainald of Dassel, gave the relics of the Three Wise Men to Cologne's cathedral in 1164 (after they had been taken from Milan). Besides the three magi Cologne preserves the relics of Saint Ursula and Albertus Magnus.