Most commercially available aural skills materials intended for use in undergraduate core curricula focus almost entirely on the study of tonal and/or twentieth-century techniques and literature. This approach, however, neglects the huge body of Medieval and Renaissance literature that provides the foundation for later Western music. Students do study this repertoire in college music curricula, of course, but often systematic study is limited to their music literature and music history coursework, with only sporadic exposure in written music theory classes (most often to sixteenth century counterpoint) and ensembles. They consequently never receive systematic aural or analytical training in music written before about 1650. Such an approach is sometimes dictated by time limitations within a four-year curriculum. However, in some cases it may be tacitly supported by music theory instructors who are not accustomed to incorporating aural study of Medieval and Renaissance literature in their curriculum. This situation may at least partially be a result of the emphasis placed on tonal and twentieth century music in the training they experienced as undergraduate music majors and as future music theory faculty.