Massive stars are the rock stars of the Universe - blazing short, intense lives, but with death resonating for generations to come! Although massive stars have a profound impact on scales from galaxies down to nearby protoplanetary discs, how they form remains poorly understood. The Star formation history of MAssive pRoTostars (SMART) project has a clear motivation: to understand the origin of massive stars and their associated star clusters that are fundamental building blocks of all the galaxies in the Universe. I propose a research plan to unveil the birth of massive protostars through the study of accretion and ejection processes. For this, I will take an observational approach using the most powerful telescopes available on Earth and in space. I will focus in the near-infrared (NIR) regime on a sample of massive protostars with both imaging and spectroscopic techniques. NIR observations are key for probing the warm regions of the inner disc and shocked and irradiated material in outflowing jets. They can also reveal the presence of nearby lower-mass stars that may be forming as part of a cluster and influencing the massive protostar. My target sample covers a wide range of evolutionary stages and environmental conditions and already has significant ancillary multi-wavelength data available in the far-infrared and radio regimes. Several recent pilot studies have demonstrated the power of NIR observations to measure key properties of these protostars yielding new insights into these systems. Now these studies need to be greatly expanded to systematically probe the evolutionary sequence and effects of environment, ultimately leading to new tests of formation theories.