While it was common in the nineteenth century to interpret the word προσήλυτος in the LXX as referring to a “foreigner,” “stranger,” or “sojourner” in a place (meanings that cohere well with the contextual sense of the Biblical Hebrew word גר, the term that προσήλυτος consistently renders in the LXX), many scholars in the twentieth century argued for the view that the word was created by Jewish Diaspora communities, or perhaps even by the LXX translators themselves, as a technical term to name Gentiles who came over to (i.e., converted to) Jewish practice and belief. While some today take issue with this latter view, the debate over the provenance and meaning of προσήλυτος continues. This article reviews and assesses this debate. It then examines the presence of the word προσήλυτος in a recently published papyrus that likely dates from the mid to late third century B.C.E.—P.Duk. inv. 727r. This new evidence lends support to the position that the term προσήλυτος was not coined by LXX translators or their wider Jewish community to name the experience of Gentile converts living among them. Rather, the word was probably selected to render the biblical term גר by virtue of the fact that it was already in use in Ptolemaic Egypt to denote a foreigner or sojourner in a region.