In the 16th century, the Church in England, confronted with the teaching of the Bible under the impulse of continental Protestantism, engaged itself in a reformation which disconnected it from many persuasions, practices and traditions of Roman Catholicism.
In particular, from the time of Henry VIII's divorce from Catherine of Aragon and subsequent marriage to Queen Anne Boleyn, it reflected on the meaning, structure and function of being a church and was involved in heated discussions on the measure according to which this reformation must occur.
After the parenthesis of Mary I, in which Roman Catholicism was restored, with Elizabeth I a line of compromise prevailed and lasted until the time of Charles I when, caused by the English Civil War, Calvinist Presbyterianism was reintroduced.
It was "the free-church ecclesiology", in which the church is mainly a free and voluntary local association of committed Christians, democratically self-managed, distinct and independent from the State.
This church must be formed, Fitz wrote, on the basis of a voluntary covenant: Being thoroughly persuaded in the conscience by the working and by the word of the almighty, that these relics of Antichrist be abominable before the Lord our God.
And last of all, inasmuch as by the workings also of the lord Jesus his holy spirit, I have joined in prayer and in hearing God's word with those that have not yielded to this idolatrous trash, notwithstanding the danger of not coming to my parish church etc.
[1]Robert Browne (1540–1630) theorized how God's faithful people are called to separate themselves from the unfaithful ones, and that the only way to form a true church is, for believers, to agree together in a covenant, the signing of which is expected by all those who wish to be part of it.