Bringing together diachronic research from a variety of perspectives, notably typology, formal syntax and semantics, this volume focuses on the interplay of syntactic and semantic factors in language change - an issue so far largely neglected both in (mostly lexical) historical semantics as well as historical syntax, but recently brought into focus by grammaticalization theory as well as Minimalist diachronic syntax. The contributions draw on data from numerous Indo-European languages including Vedic Sanskrit, Middle Indic, Greek as well as English and German, and discuss a range of phenomena such as change in negation markers, indefinite articles, quantifiers, modal verbs, argument structure among others. The papers analyze diachronic evidence in the light of contemporary syntactic and semantic theory, addressing the crucial question of how syntactic and semantic change are linked, and whether both are governed by similar constraints, principles and systematic mechanisms. The volume will appeal to scholars in historical linguistics and formal theories of syntax and semantics.