In the literature on grammaticalization, it is generally assumed that there are two categories of bound elements, clitics and affixes, and that a development from the former to the latter is an example of grammaticalization. Frequently, this development in form is assumed to be associated with a change in function. In this paper, we argue that a simple dichotomy between clitic and affix does not do justice to the variation found between bound elements, nor to the changes they undergo over time. We also argue that changes in form are not always accompanied by a change in function. We illustrate our discussion with the history and current distribution of definiteness marking in Scandinavian.