20th century: 1920 - 1929

The city acquires the building complex on Löbdergraben (no. 12-14a), which was built between 1910 and 1915, as the headquarters of the city administration.

May 1: The Imperial Law on the Formation of the State of Thuringia, in which the eight existing small Thuringian states (with the exception of Coburg) are merged, comes into force. Weimar becomes the state capital.

October 4-15: The newly elected state synod is constituted in the Rosensäle as the 1st state church congress of the Thuringian Protestant Church.

Two rooms of the Inspector's House in the Botanical Gardens are set up as the first Goethe memorial in Jena.

March 11: The constitution of the newly founded state of Thuringia is adopted. The constitution, which was essentially drafted by Jena law professor Eduard Rosenthal, is regarded as exemplary democratic, above all due to the granting of far-reaching rights to the state parliament vis-à-vis the state government.

April 1: The (comprehensive) University of Jena, previously maintained by the four Ernestine states, becomes the "Thuringian State University".

May 28/29: A memorial to the special military unit of the Blinker (signalmen), who were trained in Jena during the First World War, is inaugurated on the Landgrave.

June 18: The Gesellschaft der Freunde der Thüringischen Landesuniversität e. V. (Society of Friends of the University of Thuringia) is founded in the university auditorium with the aim of supporting the university in close cooperation with the regional economy and the university.

August 22-26: The VII Party Congress of the KPD takes place in the Great Hall of the Volkshaus. Ernst Friesland-Reuter is appointed General Secretary of the KPD.

September 19-24 : The first German Physicists' Conference is held in Jenaunder the direction of Max Wien.

October 13: "Jenaer Glas" is registered as a brand name with the German Imperial Patent Office. It initially stands for a wide range of equipment and laboratory glassware; in the 1920/30s, production is expanded to include heat-resistant household glasswith designs by Wilhelm Wagenfeld, Gerhard Marcks and Laszlo Moholy-Nagy.

November: The KPD moves its "Greater Thuringia" district leadership from Erfurt to Jena. Its political leader is Walter Ulbrichtuntil 1923 .

December 1: The Stadtbank zu Jena is opened after taking over the giro and securities department of the Stadtsparkasse. It has to close in 1938 due to liquidity problems and is incorporated into the Stadtsparkasse.

6 December: The Jenaer Wirtschaftshilfe association - also known as Jenaer Studentenhilfe - is founded in Jena as a network of local service facilities for students.

The Carl Zeiss company begins to consider relocating parts of its production from the city center. This leads to the gradual construction of the southern factory in the suburb of Lichtenhain. In a first step, buildings 23 and 23a (later VEB Jenapharm), designed by the Jena architects Schreiter&Schlag, are completed by 1924 (or 1929).

April 13: The Hochbaum-Homeyer Home - named after the two founders - on the "Schweizerhöhe" is inaugurated. It is used for the recovery of sick and malnourished children.

June 6: The Optical Museum, founded as an institution of the Carl Zeiss Foundation, is opened. In Oct. 1924, it moves to the newly constructed building of the State Optical School at Carl-Zeiss-Platz 12.

June 27: The Jena branch of the DDP holds a memorial service in the Volkshaus for the murdered Reich Foreign Minister Walther Rathenau. The main speaker is the deputy party chairman, Jena law professor Heinrich Gerland.

July 1: In response to the Rathenau murder, a "bloc of republican students" is formed at the university.

July 8: The Thuringian Teacher Training Act establishes academic elementary school teacher training at the University - against the resistance of a large part of the teaching staff.

July 31/Aug. 1: The Republican Student Cartel (also: Reichskartell der Deutschen Republikanischen Studentenschaft, from 1928: Deutscher Republikanischer Studentenbund) is founded in Jena as a union of left-wing and liberal student associations.

September 24: The Stadttheater, rebuiltby Walter Gropius and the Bauhaus workshops, is opened. The German National Theater in Weimar is responsible for the production.

October 1: The town of Lobeda and the villages of Ammerbach, Burgau, Kunitz, Löbstedt, Winzerla, Wöllnitz, Zwätzen and Göschwitz (1923) are incorporated into Jena on the basis of a state law. This increases the population of Jena to just under 56,000. Lobeda, Kunitz, Wöllnitz and Göschwitz regain the status of politically independent municipalities in 1924.

14 February: Youth organizations committed to democracy unite to form the "Jugendring Jena".

September 1: The companies Zeiss and Schott agree to support the emergency kitchen, which is primarily funded by private donations, with considerable funds each month. The facility in the Schützenhaus serves between 800 and 1,000 portions of food a day, primarily to pensioners and the unemployed. The number of unemployed people in Jena rises to 1,700 by the end of the year.

September 4: The Reich Center for Earthquake Research is founded in Jena (Am Fröbelstieg 3).

October 15: Law and economics merge at the university to form a joint faculty. With the "Rothenberg Library" - donated by the export merchant Erich Rothenberg - it has a specialist library that is outstanding throughout Germany.

Autumn: The "Thuringian university conflict" between the state government and the university escalates due to the appointment of professors not approved by the university management.

October/November: Hyperinflation reaches its peak with weekly increases in currency devaluation and inflation of up to 600%. The nationwide introduction of the Rentenmark on 15 November initiates currency stabilization.

November: The Ministry of Education appoints Emil Klein to a professorship in naturopathy , against the opposition of the Faculty of Medicine. The Polyclinic for Naturopathy (1924), founded by Klein, is one of the first of its kind at a German university.

A tuberculosis clinic is set up at Forstweg 24 for teaching and research purposes in cooperation between the Thuringian State Insurance Institute and the Tuberculosis Welfare Office at the Medical University Polyclinic. Under the leadership of Felix Lommel and Julius Emil Kayser-Petersen, their work led to a rapid reduction in tuberculosis mortality in Jena in the 1920s, and from 1930 Thuringia took on a pioneering role in coercive measures against tuberculosis patients.

The neurologist Hans Berger succeeds in recording voltage fluctuations in the human brain and develops a method for measuring brain waves with the electroencephalogram (EEG). He thus laid the foundations for modern neurological diagnostics and neuropsychology. His achievements were honored in 1940 with a nomination for the Nobel Prize.

The Urania publishing house is foundedwith the help of Julius Schaxel, Associate Professor of Zoology. With a socialist orientation, it is dedicated to the dissemination of scientific knowledge among the working class, among other things by publishing the popular science magazine "Urania".

The university professor Felix Auerbach has a residential house built in Schaefferstraße ("Haus Auerbach") by the architectural firm Gropius. It is designed according to the modular system developed by the Bauhaus.

February 10: In the elections to the Third Thuringian State Parliament in Jena, the bourgeois parties united in the "Ordnungsbund" achieve 45% of the vote, the SPD only 19%, the KPD almost 27% and national socialist groups 8%.

March 10: After the Thuringia-wide NSDAP ban is lifted, an NSDAP local group is founded in Jena.

April: The reform pedagogue Peter Petersen, who was appointed to the university in 1923 , begins the practical testing of his pedagogical concept, later known internationally as "Jenaplan pedagogy", at the experimental university school he redesigned.

June 2: A Montessori school is founded in Jena, after a children's home has already been run according to the principles of Montessori education since September 1923. Between 1924 and 1932, 25 to 30 children between the ages of six and ten are taught in a mixed-age class each year.

August 12: The first memorial to Friedrich Schiller'swork in Jena is opened in the former Schiller garden house in Schillergäßchen. It is designed by Max Vollert, who worked as a curator at the university until 1922 .

August 23: The new building of the University's Dermatology Clinic in Erfurter Straße, financed by the state of Thuringia, is handed over.

August 24: The stadium in the Oberaue (today's "Ernst-Abbe-Sportfeld"), built mainly through voluntary work by members of the 1st Jena Sports Club, is inaugurated.

October 20: The School of Optics, which opened in 1918 and was managedby Hermann Pistorfrom 1919 (until 1951) , moves into a new building on Carl-Zeiss-Platz designed by the architectural firm Schreiter & Schlag.

The Assyriologist and archaeologist Hermann Volrath Hilprecht (Philadelphia) bequeaths a collection of around 3,300 archaeological finds from the Near East to the University. It becomes accessible to the public as the "Professor Hilprecht Collection of Babylonian Antiquities" or "Hilprecht Collection of Near Eastern Antiquities".

January 5: The Jena Higher Police School, established in accordance with the Thuringian Police School Ordinance of December 15, 1924, is opened.

15 March-12 April: The Kunstverein Jena organizes a personal exhibition of the painter and Bauhaus teacher Wassily Kandinsky with around 100 paintings, watercolours and graphic works in the Prinzessinnenschlösschen.

April 1: The mathematics and natural sciences subjects at the university are separated from the Faculty of Philosophy and merged into a new Faculty of Mathematics and Natural Sciences, which also includes the Institute of Agriculture and the Psychological Institute.

November 19: Adolf Hitler speaks for the first time at a major NSDAP event in the Volkshaus.

End of the year: Abraham Esau, Professor of Technical Physics, carries out the world's first VHF transmission between Jena and Kahla.

The town hall renovation begun in 1925 by Dresden architect Emil Högg is completed. Among other things, a restaurant is installed on the first floor.

May 1: On the initiative of Adolf Reichwein - who had taken over the management of the institution from Wilhelm Flitner in 1924 - the Jena Adult Education Center is able to open a home for young workers on the Beutenberg with the support of the Carl Zeiss Foundation.

May 9-11: The first Max Reger Festival takes place as part of the Academic Concerts.

July 18: The Zeiss Planetarium is opened as the world's oldest facility of its kind. The basic form for a planetarium device based on optomechanical light projection, which had already been used as a model in Munich in 1924, was designed by the Zeiss physicist Walther Bauersfeld; the planetarium building in the Prinzessinnengarten is based on a design by the architecture firm Schreiter & Schlag.

July 23-26: The 12th Thuringian District Gymnastics Festival takes place in Jena. In addition to members of the numerous Jena gymnastics clubs, around 8,000 participants from outside the city take part.

September 15: Following the death of philosopher Rudolf Eucken, his residence in Botzstraße is opened to the public at the request of his widow Irene Eucken for the purpose of preserving and disseminating Eucken's intellectual legacy and opened in 1928.

December 18: After 7 months of construction, the Jena substation of Thüringische Landeselektrizitätsversorgungs A.G. is completed. In addition to converting the voltage from 100 to 50 kV, the plant also served to supply the electricity supply area of Jenaer Elektrizitätswerke A.-G. with 10 kV.

January 30: The SPD emerges victorious from the elections to the IV Thuringian state parliament in Jena with around 31%, while the two conservative bourgeois parties win around 28.6% of the vote.

February 7: On the initiative of Grete Unrein and the Jena Main Women's Association, the Thuringian Mothers' Home is founded in Löbstedt, which offers needy, mostly illegitimate mothers medical care and social support before and after giving birth.

April 2: The "Capitol" cinema at Löbdergraben 29 (designed by architects Schreiter & Schlag) opens. It becomes by far the most frequented movie theater in Jena.

The German National Association of Commercial Assistants acquires the castle in Lobeda, including the surrounding grounds. One of the first sports sanatoriums in Germany subsequently emerges from a youth and hiking home set up here.

June 13: The new reinforced concrete Paradise Bridge is inaugurated. It replaces the iron "Schützenbrücke" bridge built in 1882 by the Schützengesellschaft for pedestrian traffic. This is moved to the Rasenmühlen weir and serves as access to the sports fields in the Wöllnitz meadows.

9 September: A gliding hall for institutionalized gliding is built on the Windknollen.

The boathouse designed by the architectural firm Schreiter&Schlag on behalf of the Carl Zeiss Foundation for the Ernst Abbe Youth is completed in Paradies.

February 19: Wilhelm Rein - professor in Jena since 1886 - influential and last representative of the pedagogical direction of Herbartianism, dies. Rein had developed the Pedagogical Seminar with its training school into an institute of world renown and promoted the adult education movement. The vacation courses he founded for teacher training became famous.

April 10: The town museum opens a folklore branch in the Siedelhof (Altjena vineyard) behind the church.

May 29/30: The VII German Brahms Festival, organized by the Berlin Philharmonic Orchestra under Wilhelm Furtwängler, takes place in Jena.

June 1: The former military swimming pool on the Saale near Lichtenhain is reopened as the "Stadtbad" - now owned by the city. Jena's first open-air swimming pool without gender segregation is designed for around 3,000 visitors.

October 21: Another major Jena primary school building is inaugurated: the Südschule on Tatzendpromenade. Its director Paul Patzer also becomes important for Jena as a choirmaster, music critic and leader of local history walks.

November 1: Arthur and Hans Behrendt open a branch of the Wohlwert uniform-price trading company at Unterm Markt 8. It is set up according to modern retail principles developed in the USA.

November 13: The Thuringian State Gymnastics Institute for the training of gymnastics teachers and sports supervisors begins its activities (from 1934, the Institute for Physical Exercise at the University). The newly constructed building of the institute in the Oberaue is popularly known as the "Muscle Church" due to its architectural design.

November 24: A memorial to the citizens of Jena who died in the First World War is dedicated on the Hainberg (formerly Galgenberg). The city had already held a competition for this in 1921. In 1926, the Dresden architect Emil Högg was awarded the contract. The memorial was mainly financed by donations from companies and private individuals.