This is the second book in a two-volume comparative history of negation in the languages of Europe and the Mediterranean. The work integrates typological, general, and theoretical research, documents patterns and directions of change in negation across languages, and examines the linguistic and social factors that lie behind such changes. The aim of both volumes is to set out an integrated framework for understanding the syntax of negation and how it changes. While the first volume (OUP, 2013) presented linked case studies of particular languages and language groups, this second volume constructs a holistic approach to explaining the patterns of historical change found in the languages of Europe and the Mediterranean over the last millennium. It identifies typical developments found repeatedly in the histories of different languages and explores their origins, as well as investigating the factors that determine whether change proceeds rapidly, slowly, or not at all. Language-internal factors such as the interaction of syntax, semantics, and pragmatics, and the biases inherent in child language acquisition, are investigated alongside language-external factors such as imposition, convergence, and borrowing. The book proposes an explicit formal account of language-internal and contact-induced change for both the expression of sentential negation ("not") and negative indefinites ("anyone", "nothing"). It sheds light on the major ways in which negative systems develop, on the nature of syntactic change, and indeed on linguistic change more generally, demonstrating the insights that large-scale comparison of linguistic histories can offer.