  We here present our first attempt to use Globular Clusters as tracers of
their parent galaxy's formation history. Globular Cluster Systems of most
early-type galaxies feature two peaks in their optical colour distributions.
Blue-peak Globular Clusters are generally believed to be old and metal-poor.
The ages, metallicities, and the origin of the red-peak Globular Clusters are
being debated. We here present our analysis of the ages and metallicities of
the red peak Globular Clusters in the Virgo S0 NGC 4570 using deep Ks-band
photometry from NTT/SOFI (ESO program ID 079.B-0511) for the red-peak Globular
Clusters in combination with HST-ACS archival data to break the age-metallicity
degeneracy.
  We analyze the combined g, z, and Ks spectral energy distribution by
comparison with a large grid of GALEV evolutionary synthesis models for star
clusters with different ages and metallicities. This analysis reveals a
substantial population of intermediate-age (1-3 Gyr) and metal-rich (solar
metallicity) Globular Clusters. We discuss their age and metallicity
distributions together with information on the parent galaxy from the
literature to gain insight into the formation history of this galaxy.
  Our results prove the power of this approach to reveal the (violent) star
formation and chemical enrichment histories of galaxies on the basis of
combined optical and near-infrared photometry.
