Modelling stellar populations at high redshift
  Stellar populations carry information about the formation of galaxies and
their evolution up to the present epoch. A wealth of observational data are
available nowadays, which are analysed with stellar population models in order
to obtain key properties such as ages, star formation histories, stellar
masses. Differences in the models and/or in the assumptions regarding the star
formation history affect the derived properties as much as differences in the
data. I shall review the interpretation of high-redshift galaxy data from a
model perspective. While data quality dominates galaxy analysis at the highest
possible redshifts (z>5), population modelling effects play the major part at
lower redshifts. In particular, I discuss the cases of both star-forming
galaxies at the peak of the cosmic star formation history as well as passive
galaxies at redshift below 1 that are often used as cosmological probes.
Remarks on the bridge between low and high-z massive galaxies conclude the
contribution.
