Thomas Cross jr was the first music printer to capitalize on the growth of public musical performances in late-seventeenth-century England by producing cheap, single-sheet editions of the newest and most popular songs, especially those from the latest theater productions, for audience members and others in fashionable society to buy. As the country’s first specialist music engraver, he was able to produce his simple prints of individual songs unusually quickly and to sell them at a fraction of the price of the larger movable-type anthologies that remained the mainstay of established London music stationers in this period. In the absence of intellectual property laws, Cross was free to print any music he could acquire, and he soon came to be seen as a threat by composers and music stationers alike. He clearly did not enjoy good relationships with contemporary composers, and we can safely assume therefore that they did not supply him with his source materials. Given that his prints were almost always the first published editions of the theater songs to appear, how, then, did he obtain his musical texts? This article examines the hypothesis that Cross’s engravings might have derived directly from the performances on the London stage of the singers he named in the titles of his editions, and that they might reflect the singers’ interpretations of the music, “exactly engrav’d,” as Cross claimed. Comparison of the variants in Cross’s editions with readings preserved in sources that have known connections to contemporary performance demonstrates that his prints—despite their not undeserved reputation for inaccuracy—probably preserve contemporary performing practices much more closely than has hitherto been acknowledged, suggesting that their significance as sources needs to be re-evaluated, and raising broader questions about the criteria that we might need to use when making judgements about the relative authority of sources from this period if we are to become truly historically informed musical editors. Their importance will be acknowledged for the first time in the new edition of The Prophetess the author is currently preparing for the Purcell Society.