We present experimental results on single crystal CeRu2 showing that the ex
tent, of the history dependence of peak effect depends on the path followed
in the space of field (H) and temperature (T). The (H,T) regime over which
the history effect is observed is larger if the vortex lattice is prepared
by lowering T from above Te in constant H, i.e., by field cooling. We comp
are this history effect: with the very recently reported history dependence
of peak effect in detwinned single crystals of YBaCuO and 2H-NbSe2, highli
ghting the similarities and differences; We discuss the possibility of a fi
rst-order vortex solid-solid transition in CeRu2 within the realm of recent
theoretical developments in the field of vortex matter.