Stellar clusters are present in the local Universe in a variety of environments, from the current cluster formation sites in the disks of the the Antennae galaxies to the old GC population that mostly populates the halo of the Milky Way, implying that their evolution is tightly linked to that of their host galaxy. To understand the observed cluster populations, I will discuss the hypothesis that GCs are the relics of regular cluster formation at high redshift that survived until the present day. To quantitatively address this hypothesis, I will present the E-MOSAICS project, a suite of 25 present day Milky Way-mass cosmological zoom-in simulations that enables the self-consistent study of the formation and co-evolution of stellar clusters and their host galaxies through cosmic time. Using these simulations, I will explain how we can use GC populations to reconstruct the merger history of the host galaxy, with applications to the Milky Way.