Art historians and philosophers often talk about the interpretive significance of titles, but few have bothered with their historical origins. This omission has led to the assumption that an artwork's title is its proper name, since names and titles share the essential function of facilitating reference to their bearers. But a closer look at the development of our titling practices shows a significant point of divergence from standard analyses of proper names: the semantic content of a title is often crucial to the identification, individuation, and interpretation of its associated artwork. This paper represents a first step towards an empirically centred study of our titling practices. I argue that, in order to accept titles as proper names, we must first recognize the social, rather than the referential, function of naming.