Ardašīr built Qal’eh Dokhar I as a “barrier fortress” during his 3rd century founding of the Sasanian Empire in Iran. The fortress’s third floor housed his royal residence but was eventually supplanted by a greater palace he built nearby.
Because it is fortified, Qal’eh Dokhtar is technically a castle, not a palace. However, in the face of its stunning walls, who would quibble over labels? Qal’eh Dokhtar boasts perhaps the earliest example of an Iranian chartaq—a square of four arches supporting a dome—which became an important feature of traditional Iranian architecture.