Finally, scholars turn to external sources, including the testimony of early church leaders, to writers outside the church, primarily Jewish and Greco-Roman historians, who would have been more likely to have criticized the church, and to archaeological evidence.
Akhirnya, para sarjana beralih ke sumber-sumber eksternal, termasuk kesaksian dari pemimpin gereja mula-mula, penulis di luar gereja (terutama sejarawan Yahudi dan Yunani-Romawi) yang akan lebih mungkin untuk mengkritik gereja awal, serta bukti-bukti arkeologi.