  As part of a long term programme, we analyse the evolutionary status and
properties of the old and populous open cluster Trumpler 5 (Tr 5), located in
the Galactic anticentre direction, almost on the Galactic plane. Tr 5 was
observed with WFI@MPG/ESO Telescope using the Bessel $U$, $B$, and $V$ filters.
The cluster parameters have been obtained using the synthetic colour-magnitude
diagram (CMD) method, i.e. the direct comparison of the observational CMD with
a library of synthetic CMDs generated with different stellar evolution sets
(Padova, FRANEC, and FST). Age, reddening, and distance are derived through the
synthetic CMD method using stellar evolutionary models with subsolar
metallicity ($Z=0.004$ or $Z=0.006$). Additional spectroscopic observations
with UVES@VLT of three red clump stars of the cluster were used to determine
more robustly the chemical properties of the cluster. Our analysis shows that
Tr 5 has subsolar metallicity, with [Fe/H]$=-0.403\pm0.006$ dex (derived from
spectroscopy), age between 2.9 and 4 Gyr (the lower age is found using stellar
models without core overshooting), reddening $E(B-V)$ in the range 0.60 to 0.66
mag complicated by a differential pattern (of the order of $\sim\pm0.1$ mag),
and distance modulus $(m-M)_0=12.4\pm0.1$ mag.
