Giovanni Battista Piranesi's (1720-1776) architectural representations continue to bewilder first-time viewers, as well as enthrall contemporary scholars interested in the wider theoretical context of architectural figuration in late eighteenth century Europe. As argued in this dissertation, the tenets of Piranesi's distinctively inventive “maniera” were born of his physical return to the prodigious ruins of antiquity. In his embrace of the Roman campania and the ruins of Vesuvius, he unearthed the ritual origins of architectural representation. In ancient Rome, as in the Bay of Naples, Piranesi located the beginnings of artistic form in figures highly incongruous, licentious, capricious, and even, grotesque. In hundreds of pages of text and nearly a thousand etchings of building and ornamental fragments, we are witness to Piranesi’s compulsive attraction to the subterranean (be it funereal or ancient waterwork), the pastoral landscape, the buried cities of Herculaneum and Pompeii. He journeyed amongst grottos and grotesqueries, revealing his obsessive preoccupation with material metamorphosis and transformation, nature’s perpetual engagement with becoming. In these liminal sites straddling life and death, the dynamic and the static, the informal and the formal, and nature and artifice, Piranesi found ample evidence of antiquity’s use of the sinuous line whose 'licentious' manner was born of ritual practices. In the frenetic interlacing of hundreds of building artifacts and ornamental figures, Piranesi identified forms of figuration celebrated for their apotropaic functions. Ancient griffins, serpents, satyrs, and sphinxes endowed with talismanic powers proliferated throughout ancient Rome, and their presence in his etchings evidenced ancient forms of Bacchic worship of great interest to Piranesi. This was the context of architectural figuration which, increasingly obfuscated by Neo-classicism, the Enlightenment, and modernity, Piranesi sought to resurface in his etchings.