The Christianisation of the Baltic lands in the thirteenth to sixteenth centuries elicited significant linguistic and cultural reactions among the indigenous Baltic peoples (Lithuanians, Latvians, and Prussians), who retained elements of their Pagan heritage even as they adopted Christian traditions. The project ‘Old Words for a New World: Translating Christianity to Baltic Pagans’ investigates this unique cultural transition using sixteenth-century Baltic catechisms as primary sources to shed light on the way Christian religious concepts were comprehended and codified in Baltic linguistic contexts. This interdisciplinary initiative combines linguistics, the historical-comparative study of religions, computational lexicography and knowledge representation. Here, we reveal the project’s innovative research design, ontological framework, and some of its preliminary results.