  We propose affine Toda field theories related to the non-crystallographic
Coxeter groups H_2, H_3 and H_4. The classical mass spectrum, the classical
three-point couplings and the one-loop corrections to the mass renormalisation
are determined. The construction is carried out by means of a reduction
procedure from crystallographic to non-crystallographic Coxeter groups. The
embedding structure explains for various affine Toda field theories that their
particles can be organised in pairs, such that their relative masses differ by
the golden ratio.
