  We present age estimates for the newly discovered very r-process enhanced
metal-poor star HE 1523-0901 ([Fe/H]=-2.95) based on the radioactive decay of
Th and U. The bright (V=11.1) giant was found amongst a sample of bright
metal-poor stars selected from the Hamburg/ESO survey. From an abundance
analysis of a high-resolution (R=75,000) VLT/UVES spectrum we find HE 1523-0901
to be strongly overabundant in r-process elements ([r/Fe]=1.8). The abundances
of heavy neutron-capture elements (Z>56) measured in HE 1523-0901 match the
scaled solar r-process pattern extremely well. We detect the strongest optical
U line at 3859.57 A. For the first time, we are able to employ several
different chronometers, such as the U/Th, U/Ir, Th/Eu and Th/Os ratios to
measure the age of a star. The weighted average age of HE 1523-0901 is 13.2
Gyr. Several sources of uncertainties are assessed in detail.
