Mental maps and historical consciousness, which describe the spatial and temporal dimensions of worldviews, are not, as commonly stated, twentieth century concepts. Historical consciousness was coined simultaneously by several German scholars in the mid-1800s. Mental maps, used in English since the 1820s, had a prominent role in US geography education from the 1880s. Since then, the concepts have traveled between practical-technical, educational, and academic vocabularies, cross fertilizing fields and contributing to the formation of new research questions. However, when these initial periods of reflection gave way to empirical investigation, strict intra-disciplinary definitions of the concepts have strengthened disciplinary borders by excluding the interpretations of the same concepts in other fields.