A study in the scientific journal PNAS by scholars from Haifa University and the Hebrew University in Jerusalem traces the migration of the Phoenicians. Scientists analyzed the lead isotopes in three Phoenician silver caches discovered in archaeological digs at Tel Dor, Acre and Ein Hofez, which allowed them to identify where the silver came from. The silver in the oldest cache unearthed at Tel Dor came from Anatolia, while the silver in the most recent cache discovered at Ein Hofez came from the Iberian Peninsula. The authors of the study suggest that silver was the motivating factor that drove Phoenician expansion in the Mediterranean and that "the quest for silver was a major trigger for a long 'precolonization' phase, during the 10th to 9th centuries B.C." While Phoenicians are never mentioned by that name in the Old Testament, their major cities of Tyre and Sidon are mentioned frequently. In Ezekiel 27:12, we read a lament for Tyre in which it says, "Tarshish did business with you because of your great wealth of every kind; silver, iron, tin, and lead they exchanged for your wares."