In 876, under their three leaders Guthrum, Oscetel and Anwend, the Danes slipped past the Saxon army and attacked and occupied Wareham in Dorset. Alfred blockaded them but was unable to take Wareham by assault. He negotiated a peace that involved an exchange of hostages and oaths, which the Danes swore on a "holy ring" associated with the worship of Thor. The Danes broke their word, and after killing all the hostages, slipped away under cover of night to Exeter in Devon.