  We examine the dynamical evolution of both Plummer sphere and substructured
(fractal) star forming regions in Galactic Centre (GC) strong tidal fields to
see what initial conditions could give rise to an Arches-like massive star
cluster by $\sim 2$ Myr. We find that any initial distribution has to be
contained within its initial tidal radius to survive, which sets a lower limit
of the initial density of the Arches of $\sim$ 600 M$_\odot$ pc$^{-3}$ if the
Arches is at 30 pc from the GC, or $\sim$ 200 M$_\odot$ pc$^{-3}$ if the Arches
is at 100 pc from the GC. Plummer spheres that survive change little other than
to dynamically mass segregate, but initially fractal distributions rapidly
erase substructure, dynamically mass segregate and by 2 Myr look extremely
similar to initial Plummer spheres, therefore it is almost impossible to
determine the initial conditions of clusters in strong tidal fields.
