This book examines the alternation between accusative-dative and dative-accusative order in Old Florentine clitic clusters and its decline in favor of the latter. Based on an exhaustive analysis of data from medieval Florentine and Tuscan texts, this volume offers a novel analysis of the rise of the variable order, the transition from one order to the other, and the demise of the alternation that relies primarily on iconicity and analogy.