In calculating the temporal order of events introduced in discourse at least two main factors have been recognized to be relevant beyond the linear order: potential causal links between the events and aspect/tense marking on the involved verbs. While causality has been argued to play an important role in general theories of discourse structure such as Segmented Discourse Representation Theory (SDRT, Asher and Lascarides 2003), the effect of aspect/tense marking has often been discussed in theoretical approaches to tense and aspect, e.g. Kamp and Rohrer (1983) or Klein (1994). The most complete theory of the functions of aspect in the computation of temporal relations is the theory of Dynamic Aspect Trees in ter Meulen (1995). Typically, both kinds of approaches tend to ignore the importance of the particular other factor. In this paper we present the results of an empirical study that investigates the strength of the respective factors in interpreting German two-sentence discourses and the impact they have on the acceptability of such discourses. We show that both factors play a significant role, thus none of the theoretical approaches can prevail without the other. However, we also found that the effect of causality is stronger than the effect of temporal marking in some cases, which leads us to suggest that an integration of the insights of ter Meulen (1995) into SDRT is required.