204 new historical genomes reveal high inter-individual heterogeneity in most European and Mediterranean regions. Armenia and Northern Europe show genetic homogeneity unlike heterogeneous Italy, Southeastern, and Western Europe. At least 7% of individuals carry ancestry from distant regions indicating cross-Mediterranean movement. 11% are ancestry outliers with 7% traceable to specific foreign sources. Italy connects bidirectionally to many regions including Armenia and North Africa. North African ancestry appears in Italy and Austria. One outlier has more sub-Saharan ancestry modeled as Iron Age Tunisian. Southeastern Europe has Near Eastern and eastern nomadic clusters during Imperial Rome. Spatial genetic structure mirrors geography and remains stable from Bronze Age to present. F_ST shows isolation-by-distance unchanged post-Bronze Age. Simulations predict structure collapse with 4-8% long-range dispersal under panmixia. Observed stability implies lower effective migration as migrants rarely reproduced locally. Roman Empire drove transient mobility via trade, labor, military without lasting admixture. Urban graveyard effect made migrants die without reproducing. Post-Empire ruralization reduced heterogeneity preserving local structure. Prehistoric three-way admixture established by Bronze Age persisted. Armenian later cluster models as 50% earlier local plus Steppe ancestry.