Historically, Iran has been referred to as Persia by the West, due mainly to the writings of Greek historians who called Iran Persis (Greek: Περσίς), meaning "land of the Persians." As the most extensive interactions the Ancient Greeks had with any outsider was with the Persians, the term persisted, even long after the Persian rule in Greece. However, Persis (Old Persian: Pārśa; Modern Persian: Pārse) was originally referred to a region settled by Persians in the west shore of Lake Urmia, in the 9th century BC. The settlement was then shifted to the southern end of the Zagros Mountains, and is today defined as Fars Province.
After Lake Urmia, Persis then shifted over to what region?
the southern end of the Zagros Mountains,