  Events from the e+e- -> Zgamma process with hard initial state radiation
collected with the L3 detector at centre-of-mass energies between 183 GeV and
209 GeV are used to measure the mass of the Z boson. Decays of the Z boson into
hadrons or muon pairs are considered and the Z mass is determined to be 91.272
+- 0.032 (stat.) +- 0.033 (syst.) GeV, in agreement with the value measured at
the Z resonance. Alternatively, assuming this measured value of the Z mass, the
method determines the LEP beam energy, found to be 87 +- 34 (stat.) \pm 34
(syst.) MeV lower than the nominal value.
