Late Bronze Age collapse
Starting from around 1200 BC, during the Late Bronze Age collapse, around the time when the Nairi tribal confederation and Urartu begin appearing in historical records, signs of admixture decrease to insignificant levels until today. It seems that widespread destruction and abandonment of major cities and trade routes caused the Armenians' isolation from their surroundings, and their adoption of a distinct culture and identity early on in their history genetically isolated them from major admixture throughout the following millennia.