Christian humanists such as Erasmus and St. Thomas More were contemporaries of Luther who also objected to abuses within Church while not breaking from it.
Meanwhile, Luther's already-established reputation as a respected professor, as well as access to the printing press, allowed his theses and ideas to spread at a rate previously unmatched by previous reformers who had similar critiques of the Church.
"Clearly there was a kind of symbiosis between Luther and the development of the printing press," Root said. "What he was writing was able to engage lots of people. Many of them were short pamphlets that could be printed up quickly, they sold well...so he was on the cutting edge of technology and he fit what the technology needed - short, energetic things people wanted to read."
Most historians agree that Luther's original intent was not to start a new ecclesial community - that idea would have been "unthinkable at the time," Root noted. "So that's too much to say; however, it's too little to say all he want to do was reform abuses."
By 1518, his theses spread throughout Germany and intellectual Europe. Luther also continued writing prolifically, engaging in disputes with Tetzel and other Catholic critics and further developing his own ideas.
For its part, the Church did not issue an official response for several years, while attempts at discussions dissolved into defensive disputations rather than constructive dialogue. As a result, early opportunities to engage Luther's criticisms on indulgences instead turned into arguments about Church authority as a whole.
Swatting flies with a sledgehammer – Luther becomes a Lutheran
One of Luther's most well-known critics was Catholic theologian Johann Eck, who declared Luther's theses heretical and ordered them to be burned in public.
In 1519, the two sparred in a disputation that pushed Luther to his more extreme view that scripture was the only valid Christian authority, rather than tradition and the bishops.
"The Catholic critics quickly changed the subject from indulgences to the question of the Church's authority in relation to indulgences, which was a more dangerous issue," Root said. "Now you're getting onto a touchy subject. But there was also an internal dynamic of Luther's own thought," that can be seen in his subsequent writings.
In 1520, Luther published three of his most renowned treatises: The Babylonian Captivity of the Church, On the Freedom of a Christian Man, and To the Christian Nobility of the German Nation.
By that time, it was clear that what Luther thought was wrong in the Church was not just the abuse of indulgences, but the understanding of the message of Christianity on some basic levels. Besides denouncing the Pope as a legitimate authority, Luther also declared that faith alone, sola fide, was all that was necessary for salvation, rather than faith and good works.
"Luther was definitely trying to fix what was a legitimate problem, which was pelagian tendencies, or people trying to work their way into heaven," said Dr. Paul Hilliard, Assistant Professor and Chair of Church History at Mundelein Seminary. It had created a "mercantile attitude" in some people at the time of Luther – "if I do this, God will do this."
"So Luther was trying to correct these things, but the phrase I sometimes say is that Luther swatted the fly of pelagianism with a sledgehammer. In order to keep any trace of humans earning salvation out of the system, he changed the system."
Luther's distrust of human beings did not particularly spring from his criticisms of indulgences and the subsequent pushback from the Church – it was in line with most anthropological thought at the time, which tended toward a very negative view of human nature. Therefore, in his Protestant views, he sought to get rid of any human involvement wherever possible – particularly when it came to interpreting scripture and salvation.
"On the scale of beasts to angels, most people (at the time) would have us a lot closer to beasts," Hilliard noted.
The Catholic Church officially condemned Luther's theses in a papal bull, Exsurge Domine, promulgated in June 1520, and in part authored by Eck. The declaration afforded Luther a 60-day window to recant his positions, lest he be excommunicated.
But by the time the papal bull was issued, Luther had not only denounced the authority of the Pope, but had declared him an anti-Christ. The window for reconciling views was all but closed.
The popular and political reforms
Despite Luther's increasingly radical claims against the Pope and the Church, his popularity spread, due to his compelling and prolific writings and, to Luther's dismay, his populist appeal.
Luther popularized the idea of a "priesthood of all believers" to the exclusion of an ordained, ministerial priesthood. Rather than bearing an indelible mark on their soul, in Luther's view ministerial priests did not differ from the "priesthood of believers" except in office and work. This, along with his personality and background, appealed to the poor and working class of the time who were frustrated with the lavish lives of Church hierarchy, which typically came at the expense of the poor in rural areas.
"Luther was very much a populist, he was a man of the people, he was scruff, he came from sort of peasant stock, he spoke the language of the people, so I think a lot of the common people identified with him," Shreck said.
"He was one of them, he wasn't far away in Rome or a seemingly wealthy bishop or archbishop...so he appealed particularly to Germans because he wanted a German liturgy and a German bible, and the people said, 'we want a faith that is close to us and accessible'."
But Luther balked when his religious ideals spurred the Peasant's War of 1525, as peasants in rural areas of German revolted, motivated by Luther's religious language of equality. The year or so of subsequent bloody war seemed to justify those who dismissed Luther as nothing more than a social movement rather than a serious religious reformer.
In order to maintain the esteem of those higher up, Luther disavowed the unruly peasants as not part of the official reform movement, laying the groundwork for the Anabaptists to fill in the religious gaps for the peasants in the future.
However, the Peasant's War wasn't the only time the Reformation got political – or lethal. Because of the vacuum of authority that now existed in Luther's pope-less, emerging ecclesial community, authority was handed over to the local princes, who took advantage of the reformation to break from the fee-demanding Pope.
Much of Germany had embraced Lutheranism by the mid 1500s, though some parts, such as Bavaria, retained their Catholic faith.
For his part, Holy Roman Emperor Charles V officially condemned Luther's theology at the 1521 Diet of Worms, a meeting of German princes, during which Luther famously refused to recant his position with the words: "Here I stand. God help me. I can do no other."
Despite Charles V's opposition to Luther's views, he allowed for Luther's safe passage from the diet, rather than enforcing the customary execution of heretics, and thus forfeited his best chance for stomping out the Reformation at its roots.
Historians speculate that while Charles V personally opposed Luther's views, he let him live because he also saw the decentralizing of power from the Vatican as something of which he could take political advantage.
Reformation fever was also catching throughout Europe, and soon Norway, Denmark, Sweden, Switzerland and England were all following Germany's example of breaking from the Catholic Church and establishing state-run, Protestant ecclesial communities.
"I like to think of the story with the little Dutch boy with his the finger in the dyke," Shreck said. "Once the breach was made, others follows his example. Once Luther did it, it was like the domino effect."
"In a book by Owen Chadwick, he said the Reformation came not because Europe was irreligious, but because it was fervently religious," Shreck added. "This was after the black death and a lot of social turmoil – people really wanted to turn to God and seek solace in faith."
But the reformers were not all agreed on their beliefs, which led to the rise of numerous sects of Protestantism, including Calvinism, Anglicanism, and Anabaptism.
"Protestantism became very divided, though they all claimed to be doing the right thing because they believed they were maintaining the purity of the faith," Schreck said.
Root noted that once the Protestant-Catholic divide "got embedded in political differences, between southern Europe and northern Europe, between Spain and England, and so the religious differences also became national differences, that just made matters far worse."
"Once you have the wars of religion in 1546, then attitudes become very harsh. Once you start killing each other, it's hard to sit down and talk," he added.
The wars over religion would become especially pronounced in the 30 Years War of the 1600s, though at that point, religion had become more of a political tool for the state, Hilliard said.
"The 30 Years War is a really good indication that while religion was important, it was not the most important thing – it was a war between different competing princes to gain greater control of territories, during which religion was thrown into the mix," Hilliard noted.
Could the Reformation have been avoided?
The million-dollar question at the center of Reformation history is whether the Reformation and the splitting of Western Christendom could have been avoided.
"Some would say by two years into the Reformation, the theological differences already ran very deep and there was no way you were going to get reconciliation," Root said.
"But there are others who would argue that as late as the 1540s it was still possible that perhaps the right set of historical circumstances could have brought people together, and there's no way of knowing, because you can't run history again and change the variables."
"Whether one could have settled it all then short of war, there were missed opportunities for reconciliation, that's clear," he added.
Luther's fiery and rebellious personality, matched with the defiant and defensive stance that the Catholic Church took in response to his ideas, created a perfect storm that cemented the Protestant-Catholic divide.
Much of Luther's thinking remained Catholic throughout his life, Schreck noted, including his devotion to the Blessed Virgin Mary.
"I think if there had been a sincere effort on the part of the Catholic hierarchy that his concerns were legitimate, history might have gone in a different direction."
It wasn't until Pope Paul III (1534–1549), 17 years after the fated theses first made their rounds, that the Catholic Church as a whole took a serious and official look at its own need for reform, and its need to respond to the Protestant Reformation.
This is Part 1 in a three-part series on the Reformation. Part 2 will discuss the Council of Trent and the Counter-Reformation. Part 3 will discuss ecumenism today.