Old and intermediate age stellar populations in ETGs separated by the classification according to their enrichment history. SLF-ETGs (upper panel) are consistent with self-enrichment, while ACC-ETGs must have suffered either strong merging/accretion or strong internal winds. The properties of the merged galaxies can be tentatively read of as the properties of the intermediate age population, i.e. low in [α/Fe] and lower in [Fe/H] than the main body of the galaxy.