Resulting age-metallicity relation of the seven old LMC clusters studied in this work (blue symbols). For comparison, nine Milky Way GCs determined as genuine members of GSE (red symbols) are also shown. The red and black solid lines follow the parametric age-metallicity model derived by Massari et al. (2019) for GSE and the MW, respectively. The red dashed lines illustrate the associated uncertainties of the GSE model.