Timing of the last massive mergers for NGC 1380 and NGC 1427. Panel a: probability distribution of stellar orbits p(λ_z, t) in the plane of circularity, λ_z, versus stellar age, t, from our best fitting models of NGC 1380. The fraction of disk orbits, f_disk, is plotted in the top subpanel as a function of t and shows a sharp transition at t ≃ 10 Gyr, indicated by the vertical dashed line. We thus infer that the massive merger responsible for the buildup of NGC 1380’s hot inner stellar halo ended about ∼10 Gyr ago. Panel b: stellar age distribution of the disk, warm, bulge, and hot inner stellar halo components from our best fitting models of NGC 1427. Since the hot inner stellar halo has younger stellar populations than most of the bulge, with the youngest stellar population aged ∼8 Gyr, we infer that the last massive merger responsible for the buildup of the hot inner stellar halo could not have ended before that.