  (Abriged) This is a short review on the evolution of elliptical and
lenticular/S0 galaxies in the dense environment of rich clusters for look-back
times of more than half the age of the Universe. In addition, new data are
presented for the cluster Abell 2218.
  Scaling relations like the Fundamental Plane provide strong evidence that
luminous ellipticals evolve purely passively up to redshifts of z=0.8 implying
that no significant new stellar population was created during that time. This
picture is supported by tight Mg-sigma and colour-magnitude relations at
various redshifts and age/metallicity diagnostic diagrams. On the other hand,
there is a strong decline in the frequency of S0 galaxies with redshift, while
a significant proportion of the galaxies have disturbed morphologies and signs
of ongoing interaction/merging. Numerous post-starburst galaxies are found as
well as passive spiral galaxies. This raises the question whether the spiral
galaxies falling into the cluster from the surrounding field could be
transformed into S0 galaxies. A possible scenario would be that the
intracluster medium first deprives the spirals of all their gas leading to the
end of star formation. The subsequent evolution within the tidal field of the
cluster could then turn the spirals into S0 galaxies over the ages.
  The study of a great number of early-type galaxies per cluster including
sub-L* galaxies reveals, however, that this picture needs some finetuning since
the relations mentioned above have a larger spread than those based on the
observation of just a few luminous galaxies. First results are presented for 48
early-type galaxies in the cluster Abell 2218 at a redshift of z=0.18.
