  A more recent example of a great discovery in mathematical physics  was the idea of a gauge field, invented by Hermann Weyl in 1918. This idea has taken only 50 years to find its place as one of the basic  concepts of modern particle physics. Quantum chromodynamics, the most fashionable theory of the particle physicists in 1981, is  conceptually little more than a synthesis of Lie’s group-algebras  with Weyl’s gauge fields. 