Lydia, with its capital at Sardis, rose to its greatest prominence under the reign of the Mermnad dynasty (c. 700 - 546 BCE).
When Cyrus II, King of Persia, invaded Sardis in 547 BCE, it became obvious that the lack of a defensive wall protecting the lower city was not a wise choice. The Lydian king Croesus simply retreated to the upper town, and the Persian army controlled the lower city with very little resistance.
