  We report the results of XMM-Newton observations of two high redshift
quasars, one radio-loud, RX J1028.6-0844 (z=4.276) and one radio-quiet, BR
0351-1034 (z=4.351). We find that the evidence for strong excess absorption
towards RX J1028-0844 is marginal at best, contrary to previous claims. The
superior sensitivity and broader, softer energy range of XMM-Newton (0.2-10
keV) allows better determination of spectral parameters than much deeper ASCA
observations (0.8-7 keV). Our XMM-Newton observations call into question
several other ASCA results of strong absorption towards high redshift
radio-loud quasars. RX J1028.6-0844 occupies the same parameter space in broad
band spectral properties as the low redshift BL Lac objects, showing no obvious
evolution with redshift. The radio-quiet quasar BR 0351-1024 became fainter
between ROSAT and XMM observations by a factor of at least 5, but with the
present data we cannot determine whether there is an associated spectral
change. These observations do not support previous claims of weaker X-ray
emission from high redshift radio-quiet quasars. The soft X-ray spectral slope
required to reconstruct the ROSAT PSPC hardness ratio of BR 0351-1034 is about
alpha-X=3.5, the steepest X-ray slope ever observed in a high redshift quasar,
and similar to that of low redshift Narrow Line Seyfert 1 galaxies.
