Despite the Arthurian Tristan legend’s later, more popular French adaptations, it is widely accepted that the legend’s origins lie in Celtic literature. Many motifs central to the Tristan story can be found in similar early Celtic heroic narratives, but to what degree scholars can trust Irish and Welsh manuscript evidence is a question that has troubled the firm situating of several motifs of the Tristan legend in Celtic culture. Since most of our surviving Celtic material comes down to us in quite late exemplars, dating the Celtic origin of the Tristan motifs has become an incredibly challenging task, and any clear conveyance of these motifs from Celtic literature to the later continental adaptations of the Arthurian tale has been thus far inconcludable. My project seeks to shed further light on the native Celtic Tristan material by examining a more obscure text, The Meeting of Líadaine and Cuirithir, which although highly-Christianized and largely overlooked in Arthurian scholarship, contains several key Tristan legend motifs in one of the earliest complete Celtic texts we have. Further comparative work between this tale and other key Tristan-precursors, I believe, may reveal the story to be an important missing witness to the development and transmutation of the Tristan legend from its Celtic origin to the Continent.