This dissertation contributes a new paradigm for understanding the ideology of the border between Egypt and Nubia in the Ptolemaic period through a gendered and human-ecological lens. Drawing on a diverse range of evidence from Egyptian iconography to Greek fiction, the dissertation re/de/constructs the multiplicity of borders accumulated in the physical and imaginary space between Egypt and Nubia. This interdisciplinary approach to the Egyptian-Nubian border reveals unrecognized ways in which the Ptolemaic sovereigns embedded their sovereignty, their empire, and their own identity in the religious, natural, and cultural landscapes of Egypt. The first three chapters explore fluid identities in the ideology of the First Cataract border in the Ptolemaic period. These chapters are particularly influenced by Gloria Anzaldúa’s metaphorical use of the swamped border to reify the fluidity of identity, as well as the affinity between Judith Butler’s conception of gender and Thomas Nail’s conception of borders, namely that they are both fluid and performative. Fluidity, however, is not only a metaphor in this study. The dissertation shows that the yearly Nile inundation was an important conceptual tool in constructing the First Cataract border between Egypt and Nubia. The first chapter analyzes gender fluidity in the syncretism of Isis with the local Cataract inundation deities in hieroglyphic Egyptian hymns and temple doorway decorations at the Temple of Isis at Philae on the southern end of the First Cataract. The second chapter argues that the Ptolemaic king embedded himself in the Egyptian “ecological triangle”—a conceptual model that outlines the interconnectedness of the sovereign(s), the gods, and nature— in the iconography and texts of the Temple of Isis at Aswan in response to the inundation crisis of the mid-240s BCE. The third chapter explores the popular Myth of the Sun’s Eye, the iconography of which decorated temples throughout Egypt, as a border myth, which anchored Egyptian sovereignty and universal imperial ideology to the First Cataract inundation waters. The First Cataract ecotheological border was not the only ideological conception of the border between Egypt and Nubia in the Ptolemaic period. As a counterpoint to the fluvial border, the dissertation moves to the Greek fictional imaginary in the fourth chapter, namely the fictional exchanges between Queen Kandake of Nubia and Alexander the Great in the Greek Alexander Romance (3.18-24). This text provides a conception of bordering that focuses on the domination, penetration, and acquisition of foreign nations’ borders and wealth via tribute collection and imperial forms of autopsy, modeled on pharaonic forms of imperialism, Hellenistic imperial ideology, and Ptolemaic imperial practices. This dissertation fills a gap in the scholarship by providing the first study on the ideology of the Nubian-Egyptian border in the Ptolemaic period as well as the first study centering the intersections of gender and nature in Ptolemaic studies. Moreover, by centering the African milieu of Ptolemaic Egypt, this dissertation contributes to recent trends in scholarship aiming to counterbalance the Mediterranean focus of contemporary Ptolemaic studies and to diversify the study of the ancient world.