Carl Zeiss trained for four years as an apprentice mechanic. In his time, microscopes were made by Pröbeln, by trial and error. Zeiss wanted to build microscope optics from calculations instead. A first collaboration with a scientist produced no result. On 3 July 1866 the 50-year-old Zeiss began to work with Ernst Abbe, a 26-year-old lecturer in mathematical physics at the University of Jena. Abbe’s task was to put the workshop’s microscope production on a secure scientific foundation. The first microscope built from his calculations performed worse than the old ones. The work was finally completed in 1872. After that, no competing product surpassed the quality of their microscopes.