Historians have traditionally situated the end of Prehistory at the advent of writing systems and the first mentions of peoples belonging to different cultural areas, which ushered in the period known as Protohistory. On the Iberian Peninsula, this occurred at the beginning of the first millennium BC, when the Phoenicians landed on these shores. Contact with other peoples during this millennium triggered a veritable cultural revolution for the inhabitants of Iberia. Salto de línea A cultural mosaic can be identified, divided into two large areas—Iberians and Celts—although these social structures would subsequently succumb to the pressures of the Roman conquest.