  We present new constraints on the merger history of the most X-ray luminous
cluster of galaxies, RXJ1347.5-1145, based its unique multiwavelength
morphology. Our X-ray analysis confirms the core gas is undergoing "sloshing"
resulting from a prior, large scale, gravitational perturbation. In combination
with extensive multiwavelength observations, the sloshing gas points to the
primary and secondary clusters having had at least two prior strong
gravitational interactions. The evidence supports a model in which the
secondary subcluster with mass M=4.8$\pm2.4 \times$ 10$^{14}$ M$_{\odot}$ has
previously ($\gtrsim$0.6 Gyr ago) passed by the primary cluster, and has now
returned for a subsequent crossing where the subcluster's gas has been
completely stripped from its dark matter halo. RXJ1347 is a prime example of
how core gas sloshing may be used to constrain the merger histories of galaxy
clusters through multiwavelength analyses.
