  We independently redetermine the reddening and age of the globular cluster
037-B327 in M31 by comparing independently obtained multicolour photometry with
theoretical stellar population synthesis models. 037-B327 has long been known
to have a very large reddening value, which we confirm to be
E(B-V)=1.360+-0.013, in good agreement with the previous results. We
redetermine its most likely age at 12.4+- 3.2 Gyr.
  037-B327 is a prime example of an unusually bright early counterpart to the
ubiquitous ``super'' star clusters presently observed in most high-intensity
star-forming regions in the local Universe. In order to have survived for a
Hubble time, we conclude that its stellar IMF cannot have been top-heavy. Using
this constraint, and a variety of SSP models, we determine a photometric mass
of M_{GC}=(3.0+-0.5)*10^7, somewhat depending on the SSP models used, the
metallicity and age adopted and the IMF representation. This mass, and its
relatively small uncertainties, make this object the most massive star cluster
of any age in the Local Group. Assuming that the photometric mass estimate thus
derived is fairly close to its dynamical mass, we predict that this GC has a
(one-dimensional) velocity dispersion of order (72+-13)km/s. As a surviving
"super" star cluster, this object is of prime importance for theories aimed at
describing massive star cluster evolution.
