Katydid said:
OK what exactly did Martin Luther do that seperated the Protestants from the Catholics? I mean, I always knew he did something and I think it had to do with nailing papers up, call me crazy I learned this when I was a kid, but what exactly did he find wrong?
There was a concept the Middle Ages of God being a stern and unforgiving judge. Many peasants in Luther's Germany held this view, and such cataclysmic events as the Black Death, which had wiped out a third of the population of Europe in its first phase, only to return time and again, seemed to bear this imagery out.
In gerneral, people of that time were very pre-occupied with thier souls being eternally damned, and Luther too seemed to be very tormented with the fear that nothing that he could ever do would ever be sufficient to merit salvation.
The Church that Luther grew up in stressed good works which included sacraments, fasting, prayer, and for one's highest degree of security, the ascetic practices of the monastery, in which Luther hoped to find the security for his eternal soul that he longed for.
Yet even as an Augustinian monk, however, Luther was still plagued by doubt.
His epiphany came in the year 1515 when he read a phrase of St Paul which stated that "The just shal live by faith'. The phrase took on a new meaning for him, and he was struck with the idea that man would be justified, or saved, by faith, and by faith alone. Slowly, this idea led him to the belief that the pilgrimages, fasts, and sacraments and other good works that his church advocated were basically unnecessary, and that no man need either priest or pope for his own salvation.
Indulgences, and in particular an indulgence proclaimed by Leo X to raise money for the building of St Peter's Church became the issue that brough Luther's provative ideas head to head with the Church. Indulgences themselves were a elaboration of the system of penance that was a part of the doctrine of the Church from its earliest times. According to the theology, following confession and proof of contrition, the sinner recieved absolution for his sins through the sacrament of reconciliation. Even though he was now free from both the guilt of sin, and any fear of eternal damnation, yet he still owed further atonement in the form or penance both in this world and in purgatory.
The first indulgences, or remissions of these further penances that were granted by popes, were remitted to the crusaders. Later, pilgrimages could be substituted, and under the Avignonese popes, much criticized for their wordly corruption, money payments sufficed.
In spite of his natural respect for authority, and almost against his will, Luther was forced to the recognition that his beliefs were contrary to that of the Church. Even if his original intent was not to break away from the ancient church, his idea that the bible was his final authority, -and not the pope or church-, was a definite break with any teaching that had gone before.
In the Church that Luther was born into, the Church and the sacramental system were necessary components of the Christian voyage into the hereafter. In the Church he died in, this was not the case. Luther's theology of justication by faith alone was something that had not been a part of Chruch doctrine in either of the eastern or western orthodoxies. In that sense, it would be fair to say that, even if it was not his intent, Luther's teaching, as popularized as they were with the mass media, does define a clear break with the Christianity as it was practiced before.
It should also be noted that Luther remained an advocate of much of the traditions of the ancient church, such as devotion to Mary, the Real Presence, and many other of the rites and rituals of christian worship. It was the work of other Christian sects and denominations to progressively free themselves of these 'superstitious relics' of the ancient church. Nevertheless, the very nature of the Church was changed by the very import of Luther's teaching.
Certainly the corruption in some church practices in a church badly need of reform and reinvigoration, gave Luther's ideas a window of opportunity. but from a Catholic perspective(which is the only perspective in which Luther's actions could be termed wrong), to answer your question of what Luther did 'wrong', his message of justification by faith alone was contrary to the very essence of the sacramental system of the ancient church.