Understanding how galaxies form and evolve in the Universe is a key, long-term goal of Astrophysics. In this regard, our Galaxy provides unique insights because, due to its proximity, detailed galactic properties can be resolved that can unravel its formation history. For this reason, the international community and in particular European countries have made large investments in observational resources to perform Galactic research during this and the following decades (for example the Gaia mission and a number of ambitious spectroscopic surveys like WEAVE and 4MOST, among others). The extraordinary wealth of data is facilitating an unprecedented leap forward to uncover the origin and evolution of our Galaxy, with important implications for deciphering the physical processes governing galaxy evolution in general. In the last decade, there has been important progress in the understanding of the chemodynamic and accretion history of the Milky Way, in which E. Fernández-Alvar played a visible role. There is, however, an important caveat in observational analysis: the lack of a methodology to derive precise stellar ages for large, unbiased samples of stars. Without the temporal dimension it is difficult to interpret observed Galactic stellar properties in terms of the processes that led to the current configuration of the Galaxy. TEMPOS aims to develop and exploit a novel methodology to derive precise age distributions for Milky-Way (MW) stellar populations. These age distributions will be combined with the chemo-dynamical information provided by the huge spectroscopic datasets and analyzed using chemical evolution models. Altogether, this information will provide key strong constraints to evaluate theoretical models of galaxy formation and evolution, thus approaching the study of our Galaxy through a comprehensive observational and theoretical approach.