This is the first English translation of the last two theological works of Eusebius of Caesarea, Against Marcellus and On Ecclesiastical Theology . The first text was composed after the deposition of Marcellus of Ancyra in 336 to justify the action of the council fathers in ordering the deposition on the grounds of heresy, contending that Marcellus was "Sabellian" (or modalist) on the Trinity and a follower of Paul of Samosata (hence adoptionist)...