The main cause of the Latifundia system in ancient Rome was the expansion of Roman territory, particularly during the Republic. As Rome conquered new lands, wealthy elites acquired large estates known as latifundia, which were often worked by slave labor. This system significantly shifted agricultural practices from small, independent farms to massive estates operated for profit. It contributed to economic disparity, social stratification, and urbanization, as small farmers lost their lands and migrated to cities seeking work. The latifundia system ultimately played a crucial role in the socio-economic dynamics of Rome, influencing its political tensions and the later transition to the Empire.