The themes of Revelation are heavily grounded in the Old Testament, so Adventist scholarship first looks to this background before attempting interpretation. The context and overall literary structure are important for interpretation. For instance Revelation is not always chronological (e.g. Jesus' death in Revelation 12:10,11 cannot follow 11:15 where He reigns; and Babylon's activities in chapter 17 cannot follow its destruction in chapter 16), but many visions are parallel, and progressively illuminate themes. In addition to parallels, there are contrasts such as the Lamb and the beast; and the seal of God and the mark of the beast. Revelation shows a typological connection between ancient Israel's history, and church history.