[Mg/Fe] vs. [Fe/H] from MR/HR spectroscopic measurements of Fornax RGB stars (coloured filled circles/triangles). The colours represent the age in Gyr, derived from the SFH. Stars in the MW are shown for comparison (small grey points). Field stars for which the probability distribution for age could be determined are shown as filled circles, while filled triangles show stars for which no statistical age estimate could be derived. For those stars, only an age estimate is given, based on the closest distance from synthetic CMD satisfying the magnitude and metallicity constraints. Globular cluster stars are shown as open circles. Stars belonging to the high resolution samples (this study; Letarte et al. 2010) are surrounded by black open circles.