I found this interesting as former Baptist for various reasons. As a Southern Baptist I was always taught that our church went back to the time of Christ.
I found this searching the wycopedia.
Landmarkism is the belief that Baptist churches and traditions have preceded the Catholic Church and have been around since the time of John the Baptist and Christ. Proponents believe that Baptist traditions have been passed down through a succession of visible congregations of Christians that were Baptist in doctrine and practice, but not necessarily in name. This view is theologically based on Matthew 16:18 , “…and upon this rock I will build my church; and the gates of hell shall not prevail against it.” and a rejection of Catholicism as part of the historical origins of Baptists.
This lineage grants Baptist churches the status of being unstained and separate from what they see as the corruptions of Catholicism and other denominations. It also allows for the view that Baptists predate the Catholic church and is therefore not part of the Reformation or the Protestant movement. Alexander Campbell of the Restoration Movement was a strong promoter of this idea.
J. M. Carroll’s The Trail of Blood, written in 1931, is commonly presented to defend this origin’s view. Several groups considered to be part of this Baptist succession were groups persecuted by the Roman Catholic Church throughout history including Montanists, Novatianists, Donatists, Paulicians, Albigensians, Catharists, Waldenses, and Anabaptists. While some of these groups shared a few theological positions with current Baptists, many held positions that would now be considered heretical by current Baptists. It is also difficult to show historical connections between those groups which were often separated by large gaps in geography and time.
The works of John T. Christian offer the best presentation of this viewpoint.