Below is an excerpt from a 1918 historical essay by Rufus M. Jones (1863-1948), Quaker Christian and then Professor at Haverford College. Published in Harvard Theological Review, "The Anabaptists and Minor Sects in the Reformation" remains an enlightening read on the rise of Anabaptism during (and even before) the days when reformers like Luther, Calvin and Zwingli were considered the leading lights of protest against the Roman Catholic Church.
Concerning the Magisterial Reformers, even though they did what Jones describes as a "monumental piece of work" in changing the course of history, there nonetheless remained among them "much lumber, sheer dead wood, in their semi-mediaeval [sic] systems." For Jones and contrary to popular opinion (as you will see if you choose to read the essay in full), Anabaptists like Conrad Grebel, Felix Manz, William Reublin, Simon Stumpff, and Ludwig Hetzer, Baltazar Hubmaier, Menno Simon and their followers put in place socio-religious principles which "helped immensely to establish the principle of free conscience, separation of Church and State, the inalienable right of a man to be religious in his own way." In short, the Radical Reformation sowed the Baptist seeds of religious liberty and the politico-conception of a "free church in a free state."
It seems conclusively plain to me that for a person to categorically deny the deeply rooted connection Baptists seem to have to their Anabaptist forefathers, a rootedness history appears to strongly support, can only be denied through a set of a priori spectacles.
As a needed disclaimer, please know I hold no illusions that all sectors of Anabaptism were either correct or defensible. Some of the more extreme elements were flatly horrifying to our moral senses, not to mention some of the leaders embraced sub-biblical Christologies among other aberrant drifts from orthodoxy. Jones addresses the issue of diversity, if not thoroughly, then surely adequately enough in the body of his work.
As a teaser, below is a selection* taken from the Jones essay. I hope it inspires you to download the entire piece from the link provided:
As their aims grew defined, the Anabaptists endeavored
(1) to construct a Church entirely on the model of the New Testament, in every particular a copy of the apostolic pattern.
(2) This was to be a visible Church, composed only of believers, a community of saints, winnowed and separated from the unbelieving and unspiritual.
(3) This state of purity in the Church was to be preserved by a rigorous use of discipline. Those who fall below the Christian standard and become corrupt or contaminated by the world, or who compromise with the world, must be excluded by ban from membership in the Church, that is, there must be a continuous use of the winnowing fan.
(4) The Church must be completely severed from all entangling alliance with the state. The Church and State have officially nothing in common. Membership in the former is a free act. There must be no kind of compulsion in spiritual matters. Through faith and experience the Church lives and grows and enlarges its fellowship. It influences the character of those who form the State, but its authority is indirect, not direct. In the sphere of religion the State has no authority; conscience in its relation with God is to be absolutely free and untrammelled.
(5) All Christians have the same fundamental rights as the clergy have. There are no classes, no orders, no fixed distinctions. The only differences are differences of gift and function.
(6) The movement tended, though more or less unconsciously, to treat the Gospel as "a new law," to be literally followed and obeyed, very much as was done in the earlier groups of Waldenses and Lollards. Under this influence most branches of the Anabaptists refused to take oaths, set themselves against war, and denied that a Christian is allowed under any circumstances to take human life. With this rigorous literalism they also joined a moral strictness of life more extreme than that which marked any other section of the Reformation, even that of the Calvinistic churches.
(7) They not only proclaimed freedom of conscience; they bore a powerful testimony to the august authority of conscience. They arrived at the conviction that conscience is an inner sanctuary or shechinah [sic] of God Himself, and here as nowhere else they believed the voice of the living God is heard. With this exalted sense of an inner connection with the divine, they suffered and died for what seemed to them eternal truth and everlasting righteousness, and in doing so they gave a new note of emphasis to the moral worth of conscience.
*paragraphs are inserted for easier readibility