Globular cluster age distributions in the MW from Forbes & Bridges (2010), split up according to their likely progenitors from Callingham et al. (2022). The shown classifications are the MW, GSE, unassociated high-energy GCs (H-E), unassociated low-energy GCs (L-E, which was given the name Koala by Forbes 2020), the Helmi Streams (H99), Sequoia (Seq), and Sagittarius (Sag). The shaded region between 8 Gyr and 11 Gyr indicates the estimated time of the GSE merger (Belokurov et al. 2018; Helmi et al. 2018).