This paper integrates archaeological, environmental and isotopic data from Roman Iron Age
(1–400 AD) settlements in Lithuania to present an updated framework for understanding the
development of farming and agricultural landscapes during this period. The study dates the introduction
of new crop species, such as rye and oats, to around 100–200 cal AD. Notably, rye
quickly became one of the most economically important crops, coinciding with the adoption
of the infield-outfield cultivation system. This system combined intensively farmed fields in
open, well-irrigated areas near settlements with more distant swiddens used for extensive farming.
Archaeobotanical analysis, along with δ15N and δ13C isotopic measurements of charred crop
assemblages, reveals a high level of diversification in both species composition and cultivation
strategies. These findings suggest that Roman Iron Age farmers employed complex farming methods
aimed at increasing agricultural productivity and expansion while maintaining adaptability
and resilience in response to environmental challenges.