  We present: 1) a kinematic and morphological study of the giant Lya nebula
associated with the radio galaxy MRC2104-242 (z = 2.49) based on integral field
spectroscopic VIMOS data from VLT; 2) a photometric study of the host (proto?)
galaxy based on Spitzer Space Telescope data.
  The galaxy appears to be embedded in a giant (>120 kpc) gas reservoir that
surrounds it completely. The kinematic properties of the nebula suggest that it
is a rotating structure, which would imply a lower limit to the dynamical mass
of ~3 x 1e11 Msun. An alternate scenario is that the gas is infalling. Such a
process would be able to initiate and sustain significant central starburst
activity, although it is likely to contribute with less than 10% of the total
stellar mass of the galaxy.
  The near- to mid-IR spectral energy distribution of the radio galaxy suggests
the existence of a reddened, E(B-V)=0.4(+/-)0 .1$, evolved stellar population
of age >~ 1.8 Gyr and mass 5(+/-)2 x 1e11 Msun. The implied formation redshift
is z_f >~ 6. This stellar mass is similar to the stellar masses found for
massive early-type galaxies at z~2 in deep, near-infrared surveys.
