It was a republication of the gospel. He made the Bible the people's book in church, school, and house (Schaff 7:xxx).
As a German monk, theologian, teacher, preacher and university Professor, Martin Luther became not only the Father of Protestant revolution but also a man to reckon with. He even transcripted and transliterated the Greek Bible in common German language. For instance:
Luther added the word "alone" to Romans 3:28 controversially so that it read: "thus, we hold, then, that man is justified without the works of the law to do, alone through faith" (Luther http://en.wikipedia.org/wiki/Luther_Bible).
Lutheran gospel, and could read a little German, studied it with the greatest avidity as the fountain of all truth. Some committed it to memory, and carried it about in their bosom. In a few months such people deemed themselves so learned that they were not ashamed to dispute about faith and the gospel not only with Catholic laymen, but even with priests and monks and doctors of divinity (http://en.wikipedia.org/wiki/Martin_Luther).
Martin Luther changed the course of Western civilization through his interpretation of Bible and humanitarian consideration. He did not agree to Roman Catholic Bible especially when the Church was becoming a place to merchandising of religion and rituals in Europe at that time. People started loving Christ instead of fearing. For Martin Luther:
A man is abundantly and sufficiently justified by faith inwardly, in his spirit, and so has all that he needs, except insofar as this faith and these riches must grow from day to day even to the future life (Hillerbrand 16).
Luther argued that the Bible, not the Pope, was the central means to determine God's word. This was a view that was certain to raise eyebrows in Rome. Also, Luther maintained that justification, or salvation, was granted by faith alone; good works and the sacraments were not necessary in order to be saved (Hillerbrand 20).
The protest against the Church was not entirely new. In England, there had been similar protests in the 14th century; although these had been crushed. Luther gained a lot of support for his ideas because many people were unhappy with the Pope and the Church.
Martin Luther despite all his sufferings all through his crusade of love for Christ, wrote 95 Theses known as "The Disputation of Doctor Martin Luther on the Power and Efficacy of Indulgences" in 1517. These Theses further enhanced Lutherism or the protest against unjust claims made by Church officials including the Pope. And thus, emerged the Protestant aspect of the Church, first, in entire Europe and then in the world on a much wider scale. Luther's Protestant beliefs spread like a jungle's fire for they hit the hearts and minds of the people straightway.
In spite of vehement criticism, no one could really stop Luther's faith and people oriented assertions and interpretations. The then Pope declared Luther a drunken bugger. It is a well known fact that Pope Leo X3 even ordered a Professor of theology to write and produce a volume against Protestant views of Martin Luther.
Yet, the kings and princes and the people of Europe and the world supported and adopted views