Figure . Milestones in the development of theoretical chemistry (green circles) and its computational algorithmic and software expressions (red boxes) in a timeline with the key quantum mechanical developments for the field (black circles) and computational science infrastructure achievements (purple boxes). A profound reshaping of the field is occurring due to data science advances (orange boxes). It's still unclear, but future advances can emerge from quantum computing (blue boxes). For the scientific milestones, the dates correspond to the following references: Schrödinger equation, Born-Oppenheimer approximation, Kohn-Sham DFT equations, Deutsch's algorithm, Joos-Zeh's decoherence, B3LYP functional, 8 and Casida's TDDFT equations. 9