  We present the results of a numerical simulation of the history and future
development of the Pleiades. This study builds on our previous one that
established statistically the present-day structure of this system. Our
simulation begins just after molecular cloud gas has been expelled by the
embedded stars. We then follow, using an N body code, the stellar dynamical
evolution of the cluster to the present and beyond. Our initial state is that
which evolves, over the 125 Myr age of the cluster, to a configuration most
closely matching the current one.
  We find that the original cluster, newly stripped of gas, already had a
virial radius of 4 pc. This configuration was larger than most observed,
embedded clusters. Over time, the cluster expanded further and the central
surface density fell by about a factor of two. We attribute both effects to the
liberation of energy from tightening binaries of short period. Indeed, the
original binary fraction was close to unity. The ancient Pleiades also had
significant mass segregation, which persists in the cluster today.
  In the future, the central density of the Pleiades will continue to fall. For
the first few hundred Myr, the cluster as a whole will expand because of
dynamical heating by binaries. The expansion process is aided by mass loss
through stellar evolution, which weakens the system's gravitational binding. At
later times, the Galactic tidal field begins to heavily deplete the cluster
mass. It is believed that most open clusters are eventually destroyed by close
passage of a giant molecular cloud. Barring that eventuality, the density
falloff will continue for as long as 1 Gyr, by which time most of the cluster
mass will have been tidally stripped away by the Galactic field.
