This thesis is a study of how and in what ways some early Christian writers came to envision the cross as a sign, and in this context, how the cross in its shape and form is seen to generate meaning. It focusses on the Epistle of Barnabas and the writings of Clement of Alexandria. It analyses examples from within these writings where the cross is presented as a sign, but in a manner which plays on the shape and materiality of the cruciform - a process referred to as the rhetorical figuration of the cross. It explores how the cross is presented as a phenomenal form which communicates divine meaning, and how it is utilised to encourage a re-orientation of life in the crucified and risen Christ. The thesis develops a novel methodology which draws on contemporary literature on signification, materiality, and performance, to encourage a fresh appreciation of the early Christian rhetorical imaging of the cross, which draws attention to its semiotic and performative dimensions. It suggests that the rhetorical figuration of the cross involves a semiosis and performance of the cross as form and thing. It argues that this semiosis reflects and participates in, the incarnational semiosis and performance of God, as Christ in becoming human enters the world of signs and signification and, in turn, the realm of embodied performativity. It relates the figuration of the cross to the theme of performance specifically, as Barnabas and Clement identify expressions of the cross in performative contexts, in bodily posture, gesture, and object, and in scenes from Greek epic and tragedy. This thesis argues that the imagining of the cross as a sign, and therein as a phenomenal geometric form which conveys theological meaning and even presence, engages the materiality of incarnation as a semiotic and performative happening.