J. Louis Martyn and others have argued that a decision by late first-century rabbis to introduce a liturgical curse against heretics (Birkat Ha-Minim) provides the background for early Christian passages about Christians being excluded from and cursed in synagogues. More recent scholars, however, have challenged the assumption that the earliest form of Birkat Ha-Minim referred to Christians and that the rabbis controlled the synagogues. The present article defends the basics of Martyn's reconstruction while nuancing the extent of rabbinic control in the early Christian centuries. It also suggests, however, that the original of Birkat Ha-Minim may have been a Qumranian curse on the Romans. © 2009 Cambridge University Press.