Abstract
<jats:p>In the first section of this chapter, agreement is defined as a morphosyntactic phenomenon whose main feature is the presence of displaced information and the status of the constituent elements of an agreement rule is briefly dealt with. The second section devises some abstract scenarios for the diachronic emergence of agreement patterns, starting from the distinction between apparent agreement, anaphoric agreement, and local agreement. A few words are also devoted to the relationship between the operatibility of agreement rules and changes in the degree of configurationality. Concrete case studies are presented to illustrate instances of the emergence of agreement patterns, analogical spread of agreement, and complexification of agreement under different aspects. Section 3 gives instances of the emergence of agreement patterns with examples taken from Egyptian‐Coptic and Northern Ethiosemitic. Section 4 describes the case of the upper‐southern Italo‐Romance dialect of Ripatransone, where a series of gender/number agreement markers expanded from determiners to an impressively large set of parts of speech. Section 5 illustrates some types of complexification of agreement patterns that occurred in the history of some Indo‐Aryan languages.</jats:p>