  One of the major developments of twentieth century physics has been the
gradual recognition that a common feature of the known fundamental interactions
is their gauge structure. In this article the authors review the early history
of gauge theory, from Einstein's theory of gravitation to the appearance of
non-abelian gauge theories in the fifties. The authors also review the early
history of dimensional reduction, which played an important role in the
developement of gauge-theory. A description is given how, in recent times, the
ideas of gauge-theory and dimensional reduction have emerged naturally in the
context of string theory and non-commutative geometry.
