What role did the Orthodox Church play in the Reformation in the 16th Century?
The Eastern Church had split some 500 years earlier and none of the issues that led to the formation of the Protestant churches were issues in the Orthodox Church. This movement, which saw the breaking away of many churches in Northern Europe, was due mainly to a corrupt and heretical view on the use of indulgences as penance. In short people could buy their way to heaven. Also the appointment to positions in the Church was influenced by monetary contributions. In objecting to these corrupt practices much of Holy Tradition was rejected and a fall back to a reliance only on Scripture as the basis of truth emerged. At this time innovative doctrines such as salvation by faith alone were developed. All this lead to thousands of branches of Christianity due to different individual interpretations of Scripture.
The Eastern Churches continued their path unchanged under the Ottomans. Also at this time there was the rise of Orthodoxy throughout Russia. It became the center of activity for the Orthodox Church at this time even though they still held Constantinople in high honor. Here there were many monasteries and seminaries for training clergy. In short the teaching of the Church remained virtually unchanged relying of the doctrine that had been established in the Seven Ecumenical Councils as the basis of the Truth taught by the Apostles. The Tradition was passed on through the Russian Church and the Church under Muslim rule. Orthodoxy retained its unbroken historical and theological connection to the New Testament Church.