A well-established genre from the near or distant past that helps rhetors make sense of a novel situation (or constrains their ability to recognize the disjunctures between the old situation and the new) (Jamieson, 1975). "Antecedent genres are capable of imposing powerful constraints" (p. 414) and raise questions about how free the rhetor's choice is from among available means of persuasion.
Jamieson, K. M. (1975). Antecedent genre as rhetorical constraint. Quarterly Journal of Speech 61(4), 406-415.
For Jamieson (1975), the papal encyclical has its origins in the antecedent genre of the didactic ars rhetorica and Roman imperial practices; the conventions of US Presidents' State of the Union address is rooted (inappropriately, she holds) in the antecedent genre of the British King's Speech to Parliament.
Devitt (2009) uses antecedent genre to refer to genres with which students have prior knowledge; the antecedent relationship here is not within a cultural history but within a single person's experience.
Jamieson, K. M. H. (1973). Generic constraints and the rhetorical situation. Philosophy & Rhetoric 6(3), 162-170. Jamieson first explored the concept of antecedent genres in this article, though she did not name the term until her 1975 article. She also uses the term "ancestral genres" (1975, p. 406).
An even earlier use is by Alastair Fowler (1971): "a work's genre is the genre at composition, which relates to an antecedent genre, itself the cumulation of a series of earlier forms. But we are never aware of a first term of the series: we never witness the origin."
Emerging Genres class, N.C. State University, Spring 2010; Carolyn Miller