  We present new VLT spectroscopic observations of the most distant quasar
known, SDSS J1030+0524 at z=6.28 which was recently discovered by the Sloan
Digital Sky Survey. We confirm the presence of a complete Gunn-Peterson trough
caused by neutral hydrogen in the intergalactic medium. There is no detectable
flux over the wavelength range from 8450 to 8710 A. We set an improved limit on
the drop of the flux level blueward of the Ly alpha line: a factor of
  > 200. Below 8450 A the spectrum shows a rise in flux, with a large fraction
(> 60 %) of the total emission produced by few narrow features of transmitted
flux. We discuss the obvious proximity effect around this quasar, with the
presence of transmitted flux with many absorption features in a region of about
23h^{-1} comoving Mpc. If assuming the surrounding medium were completely
neutral, the size of this region would imply a quasar lifetime of \~1.3x10^7
years.
  We also present near-IR spectroscopy of both SDSS J1030+0524 and of SDSS
J1306+05, the second most distant quasar known at redshift 6.0. We combine
measurements of the CIV line and limits on the HeII emission with the NV line
measurements from the optical spectra to derive line ratios, and by implication
the abundances of these early quasar environments. The results are
indistinguishable from those of lower redshift quasars and indicate little or
no evolution in the abundances from z ~ 6 to z ~ 2. The line ratios suggest
supersolar metallicities, implying that the first stars around the quasars must
have formed at least a few hundreds of Myrs prior to the observation, i.e. at
redshift higher than 8.
