Alister McGrath defines historical theology as 'the branch of theological inquiry which aims to explore the historical development of Christian doctrines, and identify the factors which were influential in the formulation and adoption.
'[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.
[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.