The central theme of this article is the relationship between material practices, social identity categories and the duality of structure. The latter concept, linking structure and agency in Giddens’ structuration theory, is here understood as dependent upon the negotiation of categories, such as ethnicity/community, social status, religion and gender, through practices like dwelling, eating and appearing. Such practices can be interpreted from the material patterns that emerge from multi-dimensional and multi-scalar analyses of archaeological data. These ideas are worked through in a case study of Britain in the fourth and early fifth centuries AD, wherein some of the relationships between practices and institutionalized identities (such as those associated with the military) can be discerned. An emphasis on the negotiation of identities in practice also places the theme of temporality at centre-stage, offering a new perspective on the balance between reproduction and transformation in the ongoing constitution of social life.