Two popular approaches exist for studying historical theology:

1. Trace the development of particular doctrines through the ages from the earliest church to the present day.  This method has the advantage of seeing how a particular doctrine of the church, such as the Trinity, was articulated and accepted throughout the centuries.
2. Study the entire doctrine of the church from year to year.  This method has the advantage of seeing the whole of a particular ancient theologian's theology, such as how Augustine viewed salvation, the Trinity, ect.