Mesoamerica was the time-place in the New World where the memory arts of writing and calendrical notation achieved their highest forms. Both had long histories going back at least to the first millennium bc and were part of an even longer and wider history of memorials and commemorations dating millennia earlier. In this essay we consider time and memorials as social constructs and forms of practice and provide data for sequential changes in both. As commonly deployed and materialized, history and memorials are about the evolving ‘now’ and future aspirations rather than a fixed past — but they are communicated by re-presenting supposed pasts. In Mesoamerica, the things remembered, the manner of remembering them, and the reasons for doing so evolved with changing social and political institutions and circumstances.