The Acts of the Sixth Ecumenical Council—that put an end to the monothelete controversy in 680-1—have never attracted much attention of the church historians. Unjustly so, as they offer a surprisingly rich account of the most dramatic ecumenical council in church history. Below the carefully edited surface of orderly sessions, one can catch glimpses of intense diplomatic manoeuvring and of dramatic conflict that degenerated into a civil war, the dethronement of two emperors, the execution of several generals, and a momentous defeat with the Bulgars. I will attempt to show how these events are related to the condemnation of monotheletism and how the Acts have been redacted to mute conflict and emphasise consensus and the respect of procedures. On this basis, I will reflect on the mechanisms of theological diplomacy and unsuccessful conflict prevention during the monothelete controversy.