The Ligonier Ministries web site has a summary of the event that kicked off the Reformation.

Excerpt:

On October 31, 1517, Martin Luther tacked up 95 theses on the church door at Wittenberg. With this act, he hoped to provoke a discussion among the scholars about the abuses of the indulgences by the Roman Catholic Church. He was not trying to create a public furor by any means, but within a fortnight, these theses had spread through the country like wildfire. The last thing Luther had in mind was to start some kind of major controversy, but nevertheless major controversy did begin.

From the discussions at Wittenberg, the disputations began to accelerate and escalate. Copies of the theses reached Rome and critical meetings were scheduled with the young monk. In these debates, Luther was maneuvered into proclaiming publicly that he had questions about the infallibility of church councils and also that he thought that it was possible that the pope could err. In 1520 a papal encyclical was issued which condemned Martin Luther as a heretic. Luther burned the document in a public bonfire and his defiance before the church was now a matter of record.

In response, Martin Luther picked up his pen to challenge the entire penitential system of the Roman Catholic Church, which undermined in principle the free remission of sins that is ours in the gospel. By doing so, he was unswervingly advocating his commitment to sola fide, the doctrine of justification by faith alone.

In 1521, Luther was summoned to the Imperial Diet, an authoritative meeting that involved the princes of the church, called by the Emperor of the Holy Roman Empire to be held in the city of Worms in Germany. Luther was an outlaw. For him to appear at the Diet was to risk his very life; therefore, he was given safe conduct by the Emperor to attend. With a few friends, Luther traveled from Wittenberg to Worms. The eyewitnesses of that episode tell us that when Luther’s little covered wagon appeared around the corner of the bend, there were lookouts posted in the church tower at Worms. All the people were agog waiting for the arrival of this notorious person. When Luther’s caravan was sighted, people were throwing their hats in the air, blowing trumpets, and creating all the fanfare of the arrival of the hero. It was the 16th century answer to a ticker-tape parade.

Things, however, became very solemn in a hurry because the next day he appeared before the Diet. His books were stacked on a table in the room, and he was asked and ordered to recant of his writings. This surprised Luther because he thought he was going to have an opportunity to defend his writings; but the only question really of any importance that was asked of him was this: “Are these your writings?” And when he said yes, they said, “Are you ready to recant of them?”

Hollywood has their version of Luther standing there boldly with his fist in the air saying, “Here I stand!” and so on. But instead he dropped his chin on his chest and muttered something that nobody could understand, so they asked him to speak up. “What did you say?” He said, “May I have 24 hours to think about it.” And so Luther was granted a reprieve of 24 hours to return to his room to contemplate the seriousness of this occasion.

The prayer that Luther wrote in that ensuing 24-hour period was one of the most moving prayers I have ever read in my life. In that prayer, Luther cried out for God in his sense of total loneliness fearing that God had abandoned him, and proclaimed, “O Lord, I am Thine, and the cause is Thine, give me the courage to stand.”

And on the morrow, Luther was called once again back to the court and was told to reply to the question. He said to the Diet, “Unless I am convinced by sacred Scripture or by evident reason, I cannot recant, for my conscience is held captive by the Word of God, and to act against conscience is neither right nor safe. Here I stand. I can do no other. God help me.” And with that there was an instant uproar.

The Protestant Reformation emphasizes the responsibility of each person to become familiar with what the Bible teaches for themselves and to make sense of it using the laws of logic for themselves. There is an enormous focus on the individual and individual’s responsibility to puzzle theology out for himself, using the tools available to him: reason, science, Scripture, history.  The Reformation put forward the famous five Solas: “Sola Scriptura” (Scripture Alone); “Sola Gratia” (Grace Alone); “Sola Fide” (Faith Alone); “Solus Christus” (Christ Alone); and “Soli Deo Gloria” (To God Alone Be Glory).

My friend J.W. Wartick has a post about the effects of the Reformation on society as a whole.

Here’s one of the effects: (links removed)

Capitalism had already begun before the European Reformations, having its renewal start in Italian city states in the 12th Century (for a detailed and extremely interesting discussion of this, see Rodney Stark, The Victory of Reason, 71ff). The Reformation, however, provided a place for capitalism to flourish. John Calvin’s thought touched upon nearly every contemporary problem, and one of these was usury (money lending at interest). Focusing upon the cultural context of the prohibition of usury in the Hebrew Scriptures, Calvin argued that his contemporary cultural context provided a way for usury to work without being necessarily wrong. Lending money in such a fashion was essential for the later development of capitalism (Alister McGrath, Reformation Thought: An Introduction, 259-260).

The Reformation also paved the way for a “Protestant Work Ethic.” Martin Luther’s notion of the “priesthood of all believers” demolished the hard distinction between the “temporal” and “spiritual” realm which dominated the thought of the church at the time. By breaking down this barrier, hard labor was elevated. It was no longer seen as an inferior life to that of monastic withdrawal; rather, any type of work could be pleasing to God (McGrath, 256-258). In contemporary churches, one can often hear about how the engineer, the retail worker, the auto worker, and the like should all utilize their skills to the glory of God. Such thinking came directly from the Reformation.

The Reformation also accelerated scientific exploration, because Christians promoted the idea that nature held secrets about God’s existence and character.

Excerpt:

Without the Reformation, modern science would probably have developed in any event because of the ethos of rationality and the doctrine of creation conducive to it. The Reformation, however, hastened the development by criticizing scholasticism and by putting emphasis on the direct observation of nature. Luther has been called the Copernicus of theology while, on the other hand, Copernicus has been called the Luther of astronomy. Indeed, Thomas Sprat, an Anglican clergyman and an early member of the Royal Society, emphasized that there was a reformation, some would say revolution, in both philosophy and theology [3]. In natural philosophy or science, questions about nature were no longer answered primarily by quoting Aristotle and the Scholastics, but by turning to observation of and experimentation on nature itself. Similarly, after the Reformation, Protestants no longer answered questions in theology primarily by quoting scholastic philosophers and theologians, but by turning directly to the Bible. Luther interpreted Scripture by asking: what is the clear and straightforward meaning of the text? Scientists interpret nature in the simplest way using the minimum number of hypotheses.

Luther believed that the world was beginning a new age, which would bring not only a reform of religion but a new appreciation of nature. In his informal “Table Talk” he said,

We are at the dawn of a new era, for we are beginning to recover the knowledge of the external world that was lost through the fall of Adam. We now observe creatures properly …. But by the grace of God we already recognize in the most delicate flower the wonders of divine goodness and omnipotence [4].

In the last part of this statement, Luther paraphrased the words of the Apostle Paul in his letter to the Romans (Rom. 1:20).

Luther was open to the authentic scientific advances of his age [5]. He appreciated the mechanical inventions of his day.

He accepted the use of medicine in treating disease and is quoted as having said [6],

It’s our Lord God who created all things and they are good. Wherefore it’s permissible to use medicine, for it is a creature of God.

To someone who said that it is not permissible for a Christian to use medicine, Luther replied rhetorically, “Do you eat when you are hungry?” According to Andrew White [7], this attitude of Luther made the Protestant cities of Germany more ready than others to admit anatomical investigation and dissection.

Luther accepted astronomy as a science, but rejected astrology as a superstition because it cannot be confirmed by demonstration. Astrology, according to Luther, is idolatry and violates the first commandment. He was both amused and distressed by Melanchthon’s interest in astrology, a belief system that was widely accepted at the time [8].

The Reformation means good economics and good science, as well as good theology.

One problem I think was left unsolved by the Reformation, though, was how to reconcile free will with divine sovereignty.

Thankfully, Christian scholars came up with the doctrine of middle knowledge, which reconciles divine sovereignty with human freedom and responsibility, solving a problem with Reformed theology.

A very good book on middle knowledge is “Salvation and Sovereignty” by Kenneth Heathley. Highly recommended by Paul Gould.