This paper examines two types of complex predicates in Japanese from a diachronic perspective. The two-fold purpose is bring more diachronic data into the dialogue on complex predicates and to evaluate the claim by Butt and Lahiri (1998) that light verb constructions are diachronically stable. Using Japanese data it is possible to test this hypothesis. While the serial verb construction has become more restricted with time, over the centuries the light verb construction [N(-ACC) suru] has remained stable and become dramatically more frequent. Using natural written data rather than constructed examples, I demonstrate that in previous stages of Japanese - namely Old Japanese and Classical Japanese - the SVC had fewer restrictions on internal order, transitivity mismatches were possible, and motion verb grammaticalization was less developed than Modern Standard Japanese. In contrast, the suru-type light verb construction has undergone no significant changes in any attested stage of Japanese other than increase in token frequency.