So you believe there were no doctrinally sound churches until 1600? Even the church at Jerusalem was apostate?
I believe the second church age was the Smyrnaen or the Persecuted church. And Foxes Book of Martyrs has the persecutions as ten.
...Ye Shall Have Tribulation Ten Days…
Time
Persecutor Description
67 AD
Nero The Smyrna Church Age begins with Nero setting fire to Rome, and then blaming the Christians
81 AD
Domitian Declaration that no Christian should be exempt from punishment, Paul’s Timothy died in 97 AD.
108 AD
Trajan and Adrian Severe persecution against Christians from 108 to 138 AD during the time of the Bishop Ignatius
162 AD
Marcos Aurelius Marcos Aurelius, commendable in study of philosophy, sharp and fierce towards Christians.
192 AD
Severus This persecution was carried out by the will and prejudice of the people and extended into Africa.
235 AD
Maximus Numberless Christians were slain without trial and burned indiscriminately in heaps
249 AD
Decius Began because of the amazing increase in Christianity, and with the heathen temples forsaken.
257 AD
Valerian The martyrs that fell during this persecution were innumerable, their tortures and deaths painful.
274 AD
Aurelian A brief persecution that ended with the emperor’s assassination.
303 AD
Diocletian The last persecution ended with Constantine’s triumph against Rome in 313 AD
Without a bible I believe the churches relied heavily on tradition. Many to this good day worship the Virgin Mary because they have always did it this way and it gelled into a tradition. The King James Version came alive along with the Baptist church. With a bible in hand they could develop sound doctrine and not rely on tradition as in past congregations.