We describe an exploration informed by transgressionism and supported by data collected from students’ report of learning abstract algebra via curriculum materials where primary historical sources are central to their design, namely Primary Source Projects (PSPs). PSPs require students to actively engage with primary source texts written by historical mathematicians and counter students’ more traditional mathematical learning experiences. We explore the components forming transgressive triads consisting of <i>outcomes</i> of <i>transgressive actions</i> taken to overcome <i>boundaries </i>encountered in students’ study of mathematics. Particularly, we focus on transgressive actions undertaken by students and provide exemplars identified from data to empirically support our theoretical conceptualisations. We end with a discussion by proposing research that draws upon transgressions in both learning mathematics via PHS in particular and with regard to other approaches in undergraduate mathematics education which may place students in contexts in which their familiar is made unfamiliar.