  Using a new radio sample, 6C* designed to find radio galaxies at z > 4 along
with the complete 3CRR and 6CE sample we extend the radio galaxy K-z relation
to z~4.5. The 6C* K-z data significantly improve delineation of the K-z
relation for radio galaxies at high redshift (z > 2). Accounting for
non-stellar contamination, and for correlations between radio luminosity and
estimates of stellar mass, we find little support for previous claims that the
underlying scatter in the stellar luminosity of radio galaxies increases
significantly at z > 2. This indicates that we are not probing into the
formation epoch until at least z > 3.
