  We report the first likely spectroscopic confirmation of a z 10.0 galaxy from
our ongoing search for distant galaxies with ISAAC/VLT. Galaxy candidates at z
>~ 7 are selected from ultra-deep JHKs images in the core of gravitational
lensing clusters for which deep optical imaging is also available, including
HST data. The object reported here, found behind Abell 1835, exhibits a faint
emission line detected in the J band, leading to z=10.0 when identified as
Ly-a, in excellent agreement with the photometric redshift determination.
Redshifts z < 7 are very unlikely for various reasons we discuss. The object is
located on the critical lines corresponding to z=9 to 11. The magnification
factor \mu ranges from 25 to 100. For this object we estimate SFR(Ly-a)
(0.8-2.2) Msun/yr and SFR(UV) (47-75) Msun/yr, both uncorrected for lensing.
The steep UV slope indicates a young object with negligible dust extinction.
SED fits with young low-metallicity stellar population models yield (adopting
mu=25) a lensing corrected stellar mass of M*~8.e+6 Msun, and luminosities of
2.e+10 Lsun, corresponding to a dark matter halo of a mass of typically M_tot>~
5.e+8 Msun. In general our observations show that under excellent conditions
and using strong gravitational lensing direct observations of galaxies close to
the ``dark ages'' are feasible with ground-based 8-10m class telescopes.
