Tibetica antiqua represents the seminal work on Tibetan religious history by one of the foremost Tibetologists of the twentieth century. Herein, Stein discusses the cultural and religious interactions among Tibet, India, and China which resulted in what we now consider "Tibetan Buddhism" from the point of view of our earliest sources, the Dunhuang manuscripts. Stein first discusses the basic tool of religious language, and the extent to which translations from Chinese, often apocryphal, scriptures competed with translations from Sanskrit. Stein also analyzes evidence for the introduction of Buddhism to Tibet, as well as what a pre-Buddhist religion may have looked like, as distinct from modern Bon. Here, these groundbreaking articles are for the first time in the English language. They have been substantially updated, and supplemented with additional material from Stein's lectures at the Collège de France.