 The variety of ways in which the dialogue form is taken up in the medieval period alone is enough to make the form as such quite interesting. In addition, as Jacobi points out, because the dialogue, unlike the disputation and commentary, is not a school form, it was always taken up as a choice and with some degree of self-consciousness on the part of the writer (Jacobi 1999, 10). They chose this form over some other for a reason that affects the argument and the position they take. (For bibliographical listings for some 160 dialogues written from the 4th century to the 15th as well as essays on the dialogues of 19 different medieval dialogue writers, see Jacobi 1999.)