'[1] Grenz, Guretzki and Nordling describe it as, "The division of the theological discipline that seeks to understand and delineate how the church interpreted Scripture and developed doctrine throughout its history, from the time of the apostles to the present day.
The twofold function of historical theology is to show the origin and development of beliefs held in the present day and to help contemporary theologians identify theological errors of the past that should be avoided in the present.
[4] For instance, the Bible and the writings of ecumenical councils are considered as historical sources and their contents are treated as witness accounts.
Its methodological foundation and aims are similar to those used by intellectual historians researching historical epistemology, particularly those such as Matthew Daniel Eddy, who investigate the cultural connections between theology and other disciplines that existed in the past.
[6][page range too broad] An evangelical position maintains that historical theology must be aligned with the word of God or that it must always reference the Scripture.