Konrad Zuse started working on a PhD thesis containing groundbreaking research years ahead of its time, mainly the first high-level programming language, Plankalkül ("Plan Calculus") and, as an elaborate example program, the first real computer chess engine. After the 1945 Luisenstadt bombing, he flew from Berlin for the rural Allgäu, and, unable to do any hardware development, he continued working on the Plankalkül, eventually publishing some brief excerpts of his thesis in 1948 and 1959; the work in its entirety, however, remained unpublished until 1972. The PhD thesis was submitted at University of Augsburg, but rejected for formal reasons, because Zuse forgot to pay the 400 Mark university enrollment fee.
Source: Wikipedia