Date of Birth: 
Place of Birth: Ribe, Region of Southern Denmark, Denmark
About Jens Olsen
- Jens Olsen (27 July 1872 – 17 November 1945) was a clockmaker, locksmith and astromechanic who built the famous world clock located in the city hall of Copenhagen, the Rådhus.
- He was born in Ribe, Denmark.
- Ever since he was a small child, Olsen was interested in clocks and other mechanical devices.
- After hearing of the broken clock in Carsten Hauch's "A Polish Family", he dreamed of fixing that clock.
- Later, he envisioned a clock that would show every conceivable type of time, from sidereal time to the rotation of the planets.
- Olsen's father was a weaver but apprenticed Olsen to a locksmith.
- However, he remained interested in clocks and read as much as he could about them and later astronomy.
- Even after ending his apprenticeship and becoming a locksmith Olsen continued to pursue these interests. In 1897, Olsen became a journeyman and eventually ended up in Strasbourg where he saw the famous clock built by Jean-Baptiste Schwilgué in the cathedral.
- He would hide in a corner near the clock, so that he could see and examine it past the viewing hours.
- After Strasbourg, Olsen moved to Switzerland where he switched to clockmaking entirely.
- After eighteen months in Paris and a five months stay in London, he returned to Denmark to work as a superintendent at Cornelius Knudsen's establishment.
- At the same time he had his own business as a clockmaker.
- In 1905, he married Anna Sofie Kröldrup, and established his shop at her home.
- When he was about fifty, Olsen completed his calculations for the world clock he envisioned.
- He showed them to Professor Elis Strömgren who approved them.
- However, it took another twenty years to acquire the funds necessary to build the clock. « In 1943, when he was 71 years old, and Denmark was under German occupation, the Technological Institute of Copenhagen placed a workshop and staff at his disposal and work on the clock began in earnest.
- After his death in 1945 his colleague, Otto Mortensen, took over the project and, after its successful completion in 1955, prepared a detailed monograph. , the main source of information.
- »The clock was started December 15, 1955 at 3 o'clock in the afternoon.
- Unfortunately, Olsen had died ten years earlier in 1945 of thrombosis.
- His clock continues to work, and is one of the most accurate mechanical devices in the world.
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