  We present the analysis of 10 massive early-type galaxies at $z\sim1.5$. They
have been identified by means of a near-IR low resolution spectroscopic
follow-up of a complete sample of 36 bright (K' $<$ 18.5) Extremely Red Objects
(EROs, R-K'$>$ 5) selected from the Munich Near-IR ClusterSurvey (MUNICS; Drory
et al. 2001). The low resolution near-IR spectra constrain their redshift at
$1.2<z<1.7$, implying absolute magnitudes M$_{K'}<-26.0$ and stellar masses
well in excess of 10$^{11}$ M$_\odot$. Under the hypothesis of pure passive
evolution from $z\sim1.5$ to $z=0$, in the local universe they would have
luminosities L$_K\ge2.5$L$^*$. Thus, they are the high-z counterparts of the
local old massive (10$^{11}-10^{12}$ M$_\odot$) early-type galaxies populating
the bright end of the local luminosity function of galaxies. The comparison of
their spectro-photometric properties with a grid of synthetic models suggests
that the stellar populations in more than half of the sample are about
$\sim$3-5 Gyr old and 1-2 Gyr old in the remaining part. These ages imply
formation redshift $z_{f} > 2$ for all the galaxies and $z_{f} \geq 4$ for the
oldest ones. The comparison of the 4000\AA break and of the overall spectral
shape of the average spectrum of the 10 galaxies at $z\sim1.5$ with those of
their local counterpartsconfirms that field massive early-type galaxies formed
the bulk of their stellar mass at $2<z<4$, most likely over a short ($<$ 1 Gyr)
star formation time scale, consistently with the results derived from the
analysis of their individual spectro-photometric properties.
