Age-metallicity relation for the Sgr GC system. The newly discovered Sgr GCs are marked with black points, and the known Sgr GCs are represented as red diamonds. In the top panel, the green line reproduces the AMR for the MW halo GCs shown in Forbes (2020, see their Fig. 3). In the bottom panel, the solid lines reproduce the median star cluster AMR relation for the LMC (orange) and Milky Way-mass (black) galaxies in the E-MOSAICS simulations by Horta et al. (2021, see their Fig. 3).