The origin of the Milky Way globular clusters Globular clusters (GCs) are among the first baryonic structures to form at high redshift and they witnessed the earliest phases of galaxy formation. Despite their ubiquity and importance for our understanding of the stellar IMF, star formation and galaxy evolution their origin is shrouded in mystery. They could have formed in gas rich discs, similarly to young massive clusters (YMCs) that we see forming today in starburst galaxies in the Local Universe; or they may have formed in more exotic environments such as the centres of dark matter mini-haloes before the assembly of the host galaxy. These two theories make different predictions for the initial cluster mass function (ICMF). The pristine properties of GCs are affected by a Hubble time of dynamical evolution and this needs to be understood if we want to derive the initial properties of GCs. The evolution of GCs can be modelled forward in time and restricts us to limited parameter searches when using conventional methods such as direct N-body integrations. We developed an extremely fast (1000 cluster models per second) method to solve for the evolution of important GC parameters such as mass and radius that can be used in iterative studies such as Markov Chain Monte Carlo. We find indications that the properties of GCs were different from the YMCs we see in the Local Universe. The implications for the early evolution of the Milky Way and `cold tidal streams' in the Gaia era are discussed.