The Achaemenid Empire is traditionally believed to have been founded by Cyrus the Great during the middle of the 6th century B.C. In 559 B.C., Cyrus became the king of Persis, and 9 years later, defeated his overlord, the Medians. Over the next few centuries, the Achaemenids expanded their empire to the east and to the west. As their empire grew, the Achaemenid rulers intended to express this new-found authority through the use of monumental architecture. This form of architecture, known today as Achaemenid architecture, was developed from the time of Cyrus, and is said to have been finalized within two generations or so. This article seeks to discuss two specific forms of Achaemenid architecture – royal tombs (specifically the tomb of Cyrus the Great, and those at Naqsh-e-Rustam), and palace-cities (specifically Pasargadae and Persepolis).