Several of the books and websites associated with the area mention Alexander of Myndos, Apollonius of Myndos, Botryas of Myndos, and Eusebius of Myndos but this is the first time I had come across Theopompos.
A statue of Theopompos is listed as being a part of Lysander’s monument at Delphi dedicated to the victory of the Spartans over the Athenians in the last battle of the Peloponnesian war (Stuart Jones, H, Pg 136)1
The dedication is mentioned by Pausanias, a Greek traveller and geographer from the 2nd century AD. (Pausanias 10.9.7)
What I find interesting is that Theopompos is the second recorded seafaring Myndian who predates Mausolus’ synoecism of the Lelegian towns and the rebuilding of Myndos at what is now Gümüşlük. With the absence of any obvious evidence of a harbour associated with the original Lelegian hill top settlement of Myndos on Bozdağ, Prof Mustafa Şahin (Uludağ University), who has excavated finds predating the synoecism at Gümüşlük, has proposed that the harbour and surrounding area may have been inhabited prior to the construction of Mausolus’ Myndos.
1 Stuart Jones, H. 1895. Select Passages from Ancient Writers Illustrative of the History of Greek Sculpture. London: Macmillan and Co