In this experimental study, 151 middle school students explored 3 historical controversies, first reading and discussing primary source documents in groups, then writing arguments on their own. Students were either randomly assigned to an experimental condition, using argumentative schemes and critical questions as guides during discussions, or to a comparison condition in which a traditional set of questions was used to guide discussions. Students in both conditions read the same historical controversies and used the same text structure heuristic to better compare reading and writing outcomes after students participated in discussion. The findings after instruction indicate comparable reading comprehension and comparable composing skill on general writing measures across conditions. Importantly, the findings also indicate disciplinary benefits for students in the experimental condition in terms of their ability to learn historical content and regarding the quality of students' historical reasoning in their written arguments. Argument schemes and critical questions appeared particularly helpful in facilitating students' substantiation of claims and development of rebuttals.