History of Christianity
Calvin established an eldership together with a "consistory", where pastors and the elders established matters of religious discipline for the Genevan population.  Calvin's theology is best known for his doctrine of (double) predestination, which held that God had, from all eternity, providentially foreordained who would be saved (the elect) and likewise who would be damned (the reprobate).  Predestination was not the dominant idea in Calvin's works, but it would seemingly become so for many of his Reformed successors.