The headword phrase (attested only here) is the Greek equivalent of the Latin aurum coronarium, concerning which Fergus Millar's entry in OCD4 deserves quoting in full: 'Gold crowns were offered to rulers and conquerors in the ancient near east and in the Hellenistic world. Similar offerings were made from the early 2nd cent. BC to Roman generals (e.g. Plutarch Aemilius 34.5) and rapidly came to be exacted by them. A law of Caesar (59 BC) enacted that it should not be demanded until a triumph had been formally decreed. Under the empire, aurum coronarium went to the emperor alone and was exacted with increasing frequency, not only for triumphs (see Res Gestae 21; Pliny Natural History 33.54) but on imperial accessions, anniversaries, adoptions and so forth, and then became an irregular form of taxation on communities'.
Why the Suda's (unidentifiable) source here picks out Rhodes and Ankyra for special mention is unclear.
[1] Adler finds no fault with this opening, but surely a word or phrase is missing.
[2] cf. alpha 259.