We wish to study the early stages of galaxy formation using
 sample of 17 radio galaxies located in the redshift range
 z = 1.5 to 3.8. The sample has been derived in a manner
 which is unbiased relative to the dust properties. Here we
 propose continuum measurements in the far-infrared using 4
 filters (70, 90, 105 and 160 microns). The spectral energy
 distributions resulting from these ISO observations will
 be supplemented with ground based observations near 1 mm.
 The wide-band (radio-mm-FIR-optical) spectra will then be
 modelled in radiative transfer calculations, in order to
 derive the likely source configuration and to constrain
 energy source in these highly luminous galaxies.

 The proposed spectral measurements would yield, in a
 straight-forward manner, the IR luminosity, dust mass,
 dust temperature and, under reasonable assumptions, also
 the star-formation rate and gas mass. Their dependence on
 redshift would provide important clues about the time
 evolution of elliptical galaxies in the early universe.

 The radio galaxies comprising this sample either lie at
 z > 3, or in narrow windows of redshift, centred at z =
 1.5, 2.0, 2.5 and 3.0 (total 17 objects).