Mausolus has made Halicarnassus the metropolis of his Carian satrapy; the victory of the anti-Athenian coalition in the Social War brings Rhodes and Cos into his sphere of influence.

The architecture of the city, including the satrap's tomb, the Mausoleum of Halicarnassus (one of the Seven Wonders of the Ancient World), shows strong Greek influence.

The mausoleum, an enormous structure containing colossal figures of the Carian king and his queen, is planned by Mausolus himself but is built by his wife and successor, Artemisia II, who is also his sister; she rules from 353.

The architect is Pythius (or Pytheos), and the sculptures that adorn the building are the work of four leading Greek artists: Scopas, Bryaxis, Leochares, and Timotheus.

The temple-like marble tomb features an Ionic colonnade on a high base surrounded by lions; the roof is a twenty-four-step pyramid surmounted by a chariot.

The Mausoleum’s frieze depicts of Amazons battling heroes.

Mausolus' second son Idrieus succeeds his mother in 351 as satrap.