Inspired by the sight of New Zealand artefacts at the Great Exhibition, Gottfried Semper argued that cannibalism and tatouage are among the first human rites and artefacts, and form part of the cradle of society. This essay examines the manner in which Semper develops an anthropology of artefactual creation of which the effect of artefacts and their style are key features. In the second part it argues that Semper's views are very similar to those of the British anthropologist Alfred Gell, in that they both conceive of the effect of artefacts as an attributed effect that can only unfold in an interaction between humans and things. A reading confronting Semper and Gell thus implies that the latter's concept of agency should be understood as the social attribution of effects to objects. A comparison between their work helps to understand not only how Semper's hypotheses of artefactual effect can be supported by anthropological enquiry, but also how Gell's theory of the social agency of artefacts can be enriched by Semper's analyses of the style of artefacts.