Color‐magnitude diagrams of target objects, separated into M31 giants, foreground dwarfs, and background galaxy contamination. Giant candidates for which we could determine spectroscopic metallicities are color‐coded by their [Fe/H] CaT in the leftmost panel. The small numbers of metal‐poor giants that are plotted to lie to the blue of the bluest isochrone were carefully vetted and pass as likely M31 giants. If these stars are excluded from the sample, our conclusions are not affected. The solid lines are isochrone sets of Girardi et al. (2002) for an age of 12.7 Gyr and metallicities [M/H] of (left to right) −2.3, −1.7, −1.4, −1.0, −0.5, and 0.0.