Age-metallicity relation for star clusters studied in this work compared with the literature (see Table C.1). Metallicity values derived from: two-color Strömgren diagram (black diamonds); the ASteCA package by Perren et al. (2017; open circles); high-resolution spectroscopy (blue squares); integrated spectroscopy (purple triangles); low-resolution spectroscopy (green circles); RGB slope method (open triangles); RGB–HB method (gray triangles); fitting of theoretical isochrones to optical data (crosses); Washington photometry (open crosses). Red squares and open circles indicate measurements from this work presented in Fig. 6 for comparison. Overplotted theoretical models: PT98 bursting model (black solid line); HZ09 model (green dotted line).