This article responds to a call for research, made by Hock (1990) more than 30 years ago, on the subject behavior of potential non-nominative subjects in the early Indo-European languages. Hock's call was made in the wake of research into behavioral properties of non-nominative subjects in several modern languages. Since then, comprehensive studies have been carried out on the subject behavior of non-nominative subjects in the early Germanic languages, including Gothic, Old English, Old Saxon, Old High German, Old Norse-Icelandic, etc. Some preliminary work has been undertaken on Latin, while work on Ancient Greek is almost non-existent. We gather the Latin data provided so far, adding complementary evidence; we also present a complete dataset from Ancient Greek not figuring in the earlier literature. These data, pertaining to six established subject tests, show that potential non-nominative subjects behave syntactically as nominative subjects in both Latin and Ancient Greek, while an analysis in terms of object is excluded.