Heidelberg lies on the river Neckar at the point where it leaves its narrow, steep valley in the Odenwald to flow into the Rhine valley where, Northwest of Heidelberg, it joins the river Rhine at Mannheim. Heidelberg is part of a densely populated region known as the Rhein-Neckar-Triangle.
In the 5th century BC there was a Celtic fortress of refuge and place of worship on the Heiligenberg, or "Mountain of Saints". Both places can still be identified.
In 40 a fort was built and occupied by the 24th Roman cohort and the 2nd Cyrenaican cohort (CCG XXIIII and CCH II CYR). The Romans built and maintained castra (permanent camps) and a signalling tower on the bank of the Neckar, and built a wooden bridge across the Neckar. The first civilian settlements would develop under the protection of the camp. The Romans remained until 260, when the camp was conquered by German tribes.
Modern Heidelberg can trace its beginnings to the 5th century when the village Bergheim ("Mountain Home") is first mentioned in documents dated to 769. Bergheim now lies in the middle of modern Heidelberg.
In 863 the monastery of St. Michael was founded on the Heiligenberg inside the double rampart of the Celtic fortress, and around 1130 the Neuberg Monastery was founded in the Neckar valley. At the same time the bishopric of Worms extended its influence into the valley, founding Schönau Abbey in 1142. Modern Heidelberg can trace its roots to this monastery.
In 1195, the Palatinate passed to the House of Welf through marriage.
The first reference to Heidelberg can be found in a document in Schönau Abbey dated to 1196. This is considered the founding date for Heidelberg.
In 1225, Louis I, Duke of Bavaria obtained the Palatinate, and thus also the castle, which is mentioned in a document.
In 1303, two castles are mentioned; the one located further up the mountain was destroyed in a gunpowder explosion in 1537. The palace of today was then built at the site of the lower castle. In 1356, the Counts Palatine were granted far-reaching rights in the Golden Bull in addition to becoming Electors.
In 1386, the University of Heidelberg was founded by Rupert I, Elector Palatine. The University played a leading part in the era of humanism and reformation and the conflict between Lutheranism and Calvinism in the 15th and 16th centuries. Heidelberg's library, founded in 1421, is the oldest public library in Germany still intact. A few months after the proclamation of the 95 theses, in April 1518, Martin Luther was received in Heidelberg, to defend them.
In 1620, the royal crown of Bohemia was offered to the Elector, Frederick V (married to Elizabeth, eldest daughter of James VI of Scotland). He became known as the "winter king", as he only reigned for one winter until the Imperial house of Habsburg regained the crown by force. This marked the beginning of the Thirty Years' War.
In 1622, after a siege of two months, the armies of the Catholic League, commanded by Johann Tserclaes, Count of Tilly, captured Heidelberg. He gave the famous Bibliotheca Palatina from the Church of the Holy Ghost to the Pope as a present. The Catholic, Bavarian branch of the house of Wittelsbach gained control over the Palatinate and the title of Prince-Elector. In 1648, at the end of the war, Frederick V's son Charles I Louis, Elector Palatine, was able to recover his titles and lands.
In order to strengthen his dynastic power, he married his daughter Liselotte to Philip I, Duke of Orléans, the brother of Louis XIV, king of France. In 1685, after the death of Charles Louis' son Elector Charles II, Louis XIV laid claim to his sister in law's inheritance. The claim was rejected, and war ensued. In 1689, city and castle were both taken by French troops, who brought about an almost total destruction in 1693.
In 1720, religious conflicts with the citizens of Heidelberg caused the Prince-Elector Charles III Philip to transfer his residence to nearby Mannheim, where it remained until the Elector Charles Theodore became Elector of Bavaria in 1777 and established his court in Munich.
In 1742, Elector Karl Theodor began rebuilding the Palace. In 1764, a lightning bolt destroyed other palace buildings during reconstruction, causing the work to be discontinued. Heidelberg fell to the Grand Duchy of Baden in the year 1803. Charles Frederick, Grand Duke of Baden re-founded the University, named "Ruperto-Carola" after its two founders. Notable scholars soon earned it a reputation as a "royal residence of the intellect".
In the 18th century, the city was rebuilt in Baroque style on the old Gothic layout.
In 1815, the Emperor of Austria, the Emperor of Russia and the King of Prussia formed the "Holy Alliance" in Heidelberg.
In 1848, it was decided to have a German National Assembly in Heidelberg. In 1849, during the Palatinate-Baden rebellion, Heidelberg was the headquarters of a revolutionary army which was defeated by a Prussian army near Waghaeusel. Until 1850, the city was occupied by Prussian troops.
Between 1920 and 1933, the University of Heidelberg's reputation was enhanced by a number of notable physicians (Czerny, Erb, Krehl) and humanists (Rohde, Weber, Gundolf).
On March 30, 1945, US forces liberated Heidelberg from the Nazi regime. German troops left the day before, after destroying the old bridge, Heidelberg's treasured river crossing and at that time the only crossing of the river Neckar for larger vehicles.
It has been theorized that Heidelberg escaped bombing in the Second World War because the US Army wanted to use the city as a garrison after the war. In fact, as Heidelberg was neither an industrial center nor a transport hub, there was nothing worth bombing in Heidelberg and Allied air raids focused on the nearby industrial cities of Mannheim and Ludwigshafen. In 1945, the University re-opened at the initiative of surgeon Karl Heinrich Bauer and philosopher Karl Jaspers.
The "Marstall" was an arsenal of the Heidelberg Castle in which several different goods were stored. The 19th century building we see today was created in a neo-classical style. Since 1971, the "Marstall" has housed lecture halls of the university.
The old bridge is a stone bridge which was erected from 1786 to 1788. There is a medieval bridge gate on the side of the old town, originally part of its town wall. Baroque tower helmets were added as part of the erection of the stone bridge in 1788.
In the 16th and 17th century the Prince Electors added two representative palace buildings and turned the fortress into a castle. The two dominant buildings at the eastern and northern side of the courtyard were erected during the rule of Ottheinrich (1556 - 1559) and Friedrich IV (1583 - 1610). Under Friedrich V (1613 - 1619), the main building of the westside was erected, the so called "English Building".
The castle and its garden were destroyed several times (during the 30 Years' War and the Palatine war of succession). When Prince Elector Karl Theodor who resided in Schwetzingen tried to restore the castle, lightning struck the Castle in 1764 and finished all attempts to rebuild the castle. Later on, the castle was misused as a quarry - castle stones helped to build new houses in Heidelberg. This was stopped in 1800 by Count Charles de Graimberg who made any effort he could to preserve the Heidelberg Castle. In spite of its Gothic interior, it was not before 1934, that the King's Hall was added.
Today, the hall is used for festivities, e.g. dinner banquets, balls and theatre performances. During the Heidelberg Castle Festival in the summer, the courtyard is the site of open air musicals, operas, theatre performances and classical concerts performed by the Heidelberg City Orchestra.
The castle is surrounded by a park where the famous poet Johann von Goethe once walked. The Heidelberger Bergbahn funicular railway runs from Heidelberg's Kornmakt to the summit of the Königstuhl via the castle.
On the northern side of the Neckar, the Heiligenberg with the remains of the celtic fortress and the Philosophers' Walk (Philosophenweg) is located. This Walk derives its name from the fact that Heidelberg's philosophers and university teachers are said to have once walked and talked here. It shows excellent views of the old town and castle.
Heidelberg is home to one of Europe's oldest educational institutes, the Ruprecht Karls University founded in 1386, more commonly known as the University of Heidelberg. Among the prominent thinkers associated with the university over the centuries are Georg Wilhelm Friedrich Hegel, Hans-Georg Gadamer, Jürgen Habermas, Karl-Otto Apel and Hannah Arendt. Karl Drais, who invented the bicycle in 1817, was a student there. At the University of Heidelberg, chemists Posselt and Reimann discovered that nicotine was the main pharmacologically active component of tobacco. In 1860, Robert Bunsen and Kirchhoff discovered spectrum analysis here. Despite this long legacy of academic excellence, the University of Heidelberg was the first to expel all its Jewish professors and students when the Nazis rose to power.
The European Molecular Biology Laboratory, European Molecular Biology Organization, the German Cancer Research Center, Max Planck Institute for Medical Research, Max Planck Institute for Astronomy, Max Planck Institute for Nuclear Physics and Max Planck Institute for Comparative Public Law and International Law) are located in Heidelberg.
Heidelberg was the center of the epoch of "Romantik" (Romanticism) in Germany. There was a famous circle of poets such as Joseph von Eichendorff, Joseph von Görres, Arnim, and Clemens Brentano. A famous relic of Romanticism is the Philosophers' Walk (Philosophenweg), a scenic walking path on the nearby Heiligenberg, overlooking Heidelberg.
The "Romantik" epoch of German philosophy and literature, was described as a movement against classical and realistic theories of literature, an antipole to the rationality of the Age of Enlightenment. It elevated medievalism and elements of art and narrative perceived to be from the medieval period as well as folk art, nature and an epistemology based on nature, which included human activity conditioned by nature in the form of language, custom and usage.
Heidelberg consists of fourteen districts which are distributed in six sectors of the city. In the central area of the city are Altstadt, Bergheim, and Weststadt. In north Heidelberg are Neuenheim and Handschuhsheim. In the east are Ziegelhausen and Schlierbach. In the south are Südstadt, Rohrbach, Emmertsgrund, and Boxberg and in the southwest is Kirchheim. In the west are Bahnstadt, Pfaffengrund, and Wieblingen.
A new city district, tentatively named "Bahnstadt", is planned on land located within Weststadt and Wieblingen. The new district will have approximately 5,000-6,000 residents and employment for 7,000.