One of the biggest challenges in the transition to open science is making data interoperable. Normally, ontologies and vocabularies are used to describe data, but these are generally problematic for historians as existing ontologies and vocabularies are insensitive to temporal variations. Within history, the subdiscipline of historical demography is a forerunner in dealing with this problem, as it studies large-scale reconstructions of populations and life courses. Historical demographers have designed their own ontologies and vocabularies to standardize historical data. We aim to gather these schemes, so that we can standardize existing insights into a common language for historical (demographic) data.