There is morphological evidence that the activity in powerful radio galaxies could be triggered by mergers and galaxy interactions. However, nothing is known about the timescales, order of events, and the type of interaction involved. It is not yet known whether there exists an evolutionary link between radio galaxies and other merger systems such as very luminous and ultraluminous infrared galaxies (VLIRGs and ULIRGs). Here, we report preliminary results obtained from the analysis of near-ultraviolet and optical spectroscopic observations of samples of Radio Galaxies and VLIRGs-ULIRGs to investigate, through age-dating of their young stellar population, whether an evolutionary link exists between VLIRGs/ULIRGs-Radio Galaxies-normal elliptical galaxies. These results will help to understand the genesis events that lead to the formation of radio jet and quasar activity, and they will allow us to place radio galaxies in the context of hierarchical evolution models for the population of giant elliptical galaxies.