  Relativistic modelling of rotational motion of extended bodies represents one
of the most complicated problems of Applied Relativity. The relativistic
reference systems of IAU (2000) give a suitable theoretical framework for such
a modelling. Recent developments in the post-Newtonian theory of Earth rotation
in the limit of rigidly rotating multipoles are reported below. All components
of the theory are summarized and the results are demonstrated. The experience
with the relativistic Earth rotation theory can be directly applied to model
the rotational motion of other celestial bodies. The high-precision theories of
rotation of the Moon, Mars and Mercury can be expected to be of interest in the
near future.
