One of the main professional-development challenges social studies teachers face involves adjusting content and instruction to accommodate the surging population of English Language Learners (ELLs). Between the 1993-1994 and 2004-2005 school years, ELL school populations increased 68 percent to more than 5.1 million, compared to a 7.8 percent increase among non-ELL students (NCELA 2008). Because most ELLs are "mainstreamed" into content-area classrooms, the burgeoning population of non-native speakers makes instructional adaptation legally and morally imperative to provide all students with meaningful learning experiences. Providing such learning experiences is still very much an issue, even when an English for Speakers of Other Languages (ESOL) program is available to students. A short taxonomy can articulate what social studies teachers actually need to accomplish--some precise guidance on what they should be doing for ELLs, easily juxtaposed with content standards, instructional strategies, key skill domains, and dispositional objectives when crafting unit and lesson plans. This article focuses on a particular example of reconceptualizing social studies curricula through reverse-chronological history instruction, an exercise applicable to secondary ELL pull out classes and mainstream social studies classrooms alike. (Contains 1 table.)