Irish history is deeply intertwined with a rich tradition of mythological beings, including deities and monstrous figures, which have profoundly shaped various literary genres. Prominent Irish writers such as Bram Stoker, Sheridan Le Fanu, and William Butler Yeats have played a significant role in integrating and transmitting these myths through literature. Although scholarly debate persists regarding the precise sources of inspiration for Dracula, Carmilla, and The Countess Cathleen, it is evident that key mythological narratives have exerted a substantial and widely recognised influence on these works. This article examines the critical role of mythological adaptation in literary history, arguing that its impact extends beyond Irish literature to the broader literary canon. Furthermore, it underscores the necessity of engaging with mythological and historical contexts to fully comprehend literary communication as a dynamic process of cultural transmission.