On December 20, 1768, as Russian plans to launch a naval expedition into the eastern Mediterranean began to materialize, Catherine II wrote to her envoy in London, describing how her tendency to build “Spanish castles” had been awakened. While, in some ways, idealistic, Catherine’s Greek project produced several tangible successes in the early 1770s. Following the victory at Chesma, in the summer of 1770, the Russian navy established firm control over the Aegean Sea for the remainder of the war. As representatives from 22 islands accepted Russian subjecthood, an image of a future Greek Archduchy or Republic began to circulate; promoted, most notably, by Admiral Spiridov and other high-ranking Russian officials. This paper describes the new hopes and political visions the Ottoman defeats engendered among Greek commentators between the summer of 1770 and the conclusion of the war in 1774. It reads the writings of Antonis Ghikas and Eugenios Voulgaris next to petitions and letters authored by inhabitants of the islands under Russian protection, reflecting upon similarities and differences in their political vocabulary. In attempting to restore the voices and vocabulary of oft-neglected social actors to discussions of Greek political thought, the paper highlights their efforts to fashion new systems of sovereignty. In doing so, it illustrates the diversity and novelty of their political claims, revealing that the inhabitants of the Archipelagic Principality did not believe themselves to be building “Spanish castles;” to the contrary, they believed themselves to be actively creating a semi-autonomous Greek polity.