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.

Philip had turned aside to the coast of Thrace, avoiding a direct confrontation with Athens, but his intentions were clear.

Many Athenians, however, continue to believe that Philip's threat was transitory, though not Demosthenes, who in the first half of 351 denounces Philip and Macedonian imperialism in his “First Philippic.” He decries the Athenian moves to counter Philip as always being too little and coming too late, and urges the creation of a task force and larger emergency force.

He reminds the Athenians that they had once defeated the Spartans, who were as strong as Philip, and sarcastically points out that Philip would never have conquered their territories if he were as timid as the Athenians seem to be.

He concludes by challenging his countrymen to take their affairs in their own hands rather than let Philip win by default.

It is not clear how influential Demosthenes' advice is—or how influential, at this stage, it deserves to be: at about the same time, and perhaps actually after the First Philippic, Demosthenes is found advocating, in the Speech on the Freedom of the Rhodians, a foolish diversion of resources to the southeastern Aegean against the encroachments of Mausolus' family.

The situation there is, in fact, beyond repair.

The goading First Philippic fails to rouse the Athenians but they do send a small contingent in September 351 when Philip lays siege to a place called Heraeum Teichos.