We construct a Lax pair with spectral parameter for the elliptic Calog
ero-Moser Hamiltonian systems associated with each of the finite-dimen
sional Lie algebras, of the classical and of the exceptional type. Whe
n the spectral parameter equals one of the three half periods of the e
lliptic curve, our result for the classical Lie algebras reduces to on
e of the Lax pairs without spectral parameter that were known previous
ly. These Calogero-Moser systems are invariant under the Weyl group of
the associated untwisted affine Lie algebra. For non-simply laced Lie
algebras, we introduce new integrable systems, naturally associated w
ith twisted affine Lie algebras, and construct their Lax operators wit
h spectral parameter (except in the case of G(2)). (C) 1998 Published
by Elsevier Science B.V.