In the 19th century, the Roman Catholic Church was under frequent attacks from the rising tide of liberal nationalism, which saw the existence of a multi-national Church loyal to the Pope has a threat to national unity. The Third Republic of France attacked the loyalty of the clergy to Rome and tried to make the priesthood dependent upon the state. The newly created secular Italian kingdom was eager to suppress the influence of the Catholic Church, and following the seizure of Rome in 1870, the papacy was deprived of what remained of its temporal powers. At the turn of the last century, the Holy Roman Emperor Joseph II had instituted a policy that has come to be known as "Josephinism", by which all contemplative orders and religious institutes which were not "useful" were disbanded or suppressed. At every turn, the Church found itself attacked and its privileges curtailed by the legislative actions of great states of the west, all who claimed to be acting on behalf of the "people."
One of the most virulent and best known of these attacks on the Church was the German Kulturkampf ("Cultural Struggle"). The Kulturkampf refers to the efforts of Imperial Chancellor Otto von Bismarck to break the influence of the Roman Catholic Church in the newly established German Empire. It is difficult to date the Kulturkampf, but most historians place it between 1871 and 1878. During the Kulturkampf, the Iron Chancellor used political and social pressure to restrict the rights of the Catholic clergy and remove the power of Catholic education from the Church by transferring it to the State.
Political Situation of the Catholic Party in Germany in 1870
Any examination of the Kulturkampf must begin by understanding the political context. Bismarck, always a great pragmatist, did not set off initially to get into a war with the Catholic Church. His initial aims were much more restricted and had as their aim the breaking up of the powerful Catholic Party (called the Centrum) in the Imperial Assembly (Reichstag). Both Bismarck's conservative bloc as well as Germany's National Liberals feared the power of the Centrum which, though not a majority, was large enough to be capable of pulling an election one way or another. In 1870-71, the Centrum was the second largest party.
Thus, the existence of the Catholic Centrum constituted a perpetual annoyance to the liberals and conservatives, which were dominated by secularists and Protestants respectively and had no desire to see a powerful Catholic minority party. Political and social considerations came together here, and Bismarck's conservatives and the National Liberals found common ground in their mutual dislike of the Centrum and the influence of the Church.
This antipathy was heightened with the proclamation of the dogma of Papal Infallibility at Vatican I in 1870, the same year Bismarck and the Prussians proclaimed the creation of the German Reich after their victory over France in the Franco-Prussian War. The doctrine of Papal Infallibility represented a threat to every secularized state in Europe, as it reaffirmed that the fundamental allegiance of every Catholic was not to his nation-state, but to the Gospel and the Church, and that the Pope's teaching was absolutely authoritative and binding on all the faithful. The proclamation of the dogma, in conjunction with Bl. Pius IX's statements on the rights of the Church in relation to civil society as laid down in the 1864 encyclical Quanta Cura, left many secular politicians wondering if Catholicism and allegiance to the modern liberal state were not mutually exclusive. For example, the influential British Prime Minister William Gladstone's pamphlet, The Vatican Decrees and Their Bearing on Civil Allegiance (1874), in which Gladstone argued that the teaching on Papal Infallibility compromised the allegiance of faithful English Catholics. 
Relations between Prussia and the Holy See in 1870
Bismarck had not initially attributed much importance to the affairs of the Council, although the Prussian Ambassador at the Holy See, Count Arnim, recommended a more active policy. Bismarck, recognizing that Prussia was a Protestant power, seemed content to follow the lead of other Catholic allies, like the Austrian Empire. In fact, relations with the Holy See in 1870 were not at all cold. Following the loss of the papal states, the Prussian Archbishop of Posen, Count von Ledochowsky, S.J., met Bismarck at Versailles during the closing days of the Franco-Prussian War and made overtures to the Chancellor on behalf of the Holy See. Ledochowsky had two requests: (1) That Bismarck and the newly established German Empire would protest the destruction of the Papal States, and that (2) the Pope would be offered asylum in Prussia if and when it became necessary to flee Rome. Bismarck categorically rejected the first request, not wanting to poison relations with the new Kingdom of Italy. But he was inclined to entertain the idea of a papal exile in Prussia, seeing obvious political benefits to hosting the Holy Father.
The above episode came to nothing, of course, but it demonstrates that Bismarck was not absolutely opposed to some understanding with the Holy See. Bismarck was no Robespierre; his opposition to the Church was pragmatic, not dogmatic. He was quite willing to help the Pope in international affairs provided the Pope would do something for Prussia. In Bismarck's case, this was to ask the Catholic deputies of the Centrum to vote with the government and against the opposition, a plea Bismarck had continually made to Pius IX since Bismarck came to power in 1862. Bismarck told Archbishop Ledochowsky in Versailles: "If we give asylum to the Pope, he must do something for us in return," meaning use his authority to align the Centrum with the policies of Bismarck. "The opposition of the ultramontane party [in the Reichstag] would be checked." How could the Catholic Centrum protest against Bismarck's policies by appealing to loyalty to the Pope if the Pope supported Bismarck?
Attack on the Centrum Backfires
The leader of the Centrum was Ludwig Windthorst, one of the foremost parliamentarians in German politics in the late 19th century. He was despised by Bismarck, and as the foremost champion of Catholicism in German politics, he was likewise despised by the secular liberals and by the Protestant conservatives. Bismarck's dislike of Windthorst went well beyond the personal; in a famous quote, which may be apocryphal, Bismarck is alleged to have said, "Everyone needs somebody to love and somebody to hate. I have my wife to love and Windthorst to hate."  Windthorst, however, was a classy opponent. He never descended to the level of the mere personal that characterized Bismarck, and he always controlled his temper even when Bismarck lost his. Because of his fundamental charitable disposition, even towards enemies, Windthorst was held in high respect by his opponents, even when they disagreed with him.
Bismarck was highly irritated when Pope Pius IX refused to meddle in Prussian parliamentary affairs on behalf of the government. Still wanting to find a way to exploit the Pope's difficulties, he proposed to the Holy See that perhaps Pius IX would be willing to publicly oppose the Centrum. This demonstrates Bismarck's misunderstanding of the nature of the Church in general and Pius IX in particular; that the pope of Vatican I and the Syllabus could be persuaded to condemn Germany's Catholic party for political expediencies was profoundly ignorant. When the papacy refused to do so, Bismarck resorted to manipulative propaganda: when Papal Secretary of State Cardinal Giacomo Antonelli made some comments on the question of the Centrum, Bismarck published them out of context, in such a way as to suggest that the Pope had come out against the Catholic party in Germany. This underhanded attempt at manipulating Catholic opinion backfired, however, for the Centrum got the ear of the Secretary of State and induced him to issue a clarification which forcefully reaffirmed Pius IX's support for the Centrum. This dashed Bismarck's hopes and exposed his underhanded manner of dealing with the Cardinal's Statements.
The Kulturkampf is Declared
Perhaps because he was embarrassed publicly, or perhaps just because he did not like being told no, Bismarck now went on the offensive. On June 19, 1871, he strongly attacked the Centrum in the conservative paper Kreuz-Zeitung. A few weeks later, he abolished the Catholic Department in the Prussian Kultus-Ministerium, the department of the Prussian government responsible for cultural matters. He bitterly attacked the Centrum in parliamentary speeches and called Ludwig Windthorst a Reichsfeind, that is, an enemy of the Empire. The Catholic Windthorst responded with all the clarity and imperturbability of Thomas More: "The Chancellor is not the State. Up until now, no minister has been so presumptuous as to call his opponents enemies of the State." 
The attacks on the Centrum went to a new level when Bismarck was joined by Professor Rudolf Virchow of Berlin, a progressive liberal parliamentarian who coined the term Kulturkampf and who believed that the struggle would free the German schools from clerical influence, both Catholic and Protestant. Under Virchow's demagoguery, anti-clericalists joined the struggle, even those who were opponents of Bismarck. Conservative Protestant parliamentarians, on the other hand, saw the struggle as a means to come out against that perennial bugbear of Protestantism, the Jesuit order. Basically, a broad coalition began to form across multiple party lines, all of whom for one reason or another saw a restriction of the rights of the Catholic clergy as necessary. It has been estimated that probably two-thirds of the population supported the efforts of Bismarck, Virchow and their allies.
Anti-Catholic Legislation of the Kulturkampf Period
It is not certain whether Bismarck at the outset conceived of the struggle in terms of actual legislation aimed at curbing the influence of the Church itself; his initial thought seems to have been simply to break the power of the Catholic Centrum. But, under the instigation of Virchow and others, what was originally a very limited political objective was transformed into a broader social battle against Catholicism as such, beyond the scope of what Bismarck initially intended. Nevertheless, perceiving the power of the movement he had helped unleash, Bismarck was quite content to ride the wave of anti-Catholic sentiment and supported the legislation of the Kulturkampf vigorously.
It is important to note that, with the exception of an anti-Jesuit bill pushed through the Reichstag in 1872, all of the laws of the Kulturkampf were passed in the Prussian Landtag and were applicable only in the State of Prussia, though some other states like Baden and Hesse followed with anti-Catholic laws of their own. Imperial Germany was a federation, composed of several German states which each retained their own regional parliaments and laws. Prussia, of course, was the largest and most powerful of these states, and the way Prussia went tended to determine the course of the whole empire. But it important to keep in mind that the Kulturkampf was primarily a phenomenon restricted to the federal state of Prussia; some Catholic states, like Bavaria, did not participate in it.
The first law of the Kulturkampf was an imperial anti-Jesuit law passed in 1872, which even appeared harsh to some of the liberals. The Law of 1872 authorized the government to dissolve all chapters of the Society of Jesus and to banish its members from the country (Jesuitengesetz). The Jesuits subsequently left the Empire. The next year the law was extended to the Redemptorists, Lazarists, Fathers of the Holy Ghost, and the Ladies of the Sacred Heart, as being closely related to the Jesuits, whereupon these orders also left Germany. Although most portions of the Kulturkampf were repealed with time, the Jesuits remained banned in Germany for the duration of the Empire.
In 1871, the criminal code was modified to infringe on clerics' right to freedom of speech. In the so-called Kanzelparagraph ("Pulpit Laws"), clergy who discussed politics from the pulpit could be sentenced to two years in prison. The Kanzelparagraph would remain in force throughout the Weimar period and would be used by Hitler to stifle the political opposition of the Church. It was not in fact revoked until 1953.
The heart of the Kulturkampf legislation was the Prussian School Supervision Law of 1871 touching on Catholic education. Like Julian the Apostate, Bismarck knew the Church was too powerful to be destroyed and instead sought to weaken her influence by driving her out of education. The law simultaneously extended civil service supervision to religious education and abolished ecclesiastical oversight of the Prussian primary school system, which up until then had been conducted by religious and secular authorities working together. This meant the practical exclusion of the clergy from education.
Bismarck also attacked the education of the clergy through his new Kultus-Minister, Adalbert Falk. To Falk was given the task of making the German bishops independent of Rome, the clergy independent of the bishops, and all dependent on the State. Falk devised a plan by which the traditional regimen of clerical study was to be replaced by a modern education in a liberal German institution, thus ensuring that candidates to the priesthood were imbibed with the spirit of secularism. Furthermore, Falk proposed that ecclesiastical offices could only be filled with the permission of the highest civil authority in each province, essentially reviving the ancient practice of lay investiture. Like Henry VIII, Falk and Bismarck wanted their national clergy exempt from any legal juridical body outside of the nation. Hence, judgments of the Holy See or the Roman Rota would not be binding upon them; the highest court would be made up of Prussian ecclesiastics, all of whom would have been appointed with the permission of Prussian civil authorities. Falk sought to restrict the Church's juridical and punitive powers by allowing any cleric to appeal to a Prussian "Royal Court of Justice for Ecclesiastical Affairs" that would consist of lay civil officials. This was to help facilitate the great apostasy, so that those clerics who chose to compromise with the State would not find themselves inconvenienced by decrees or punitive measures coming from Rome. In short, the proposals of Falk set out to establish a national Prussian Church, in which education of the clergy, appointments, and discipline were under the control of the State.
Falk went even further in his law which forbid any priest to exercise his priestly duties without authorization of the civil power on pain of imprisonment, and threatened bishops who opposed it. Falk and Bismarck here underestimated the resolve of the Catholic faithful. Rather than conform and obtain the hated "authorization", most Catholic priests chose to simply continue their duties clandestinely, or else cease their ministries. This in effect left large amounts of the Catholic population without access to sacraments, a state of affairs which thoroughly angered them and give rise to a national backlash against the laws.
Patronage of Old Catholics
A large part of the Kulturkampf was not only the persecution of Catholics, but the patronage of the Old Catholics, who in that decade after Vatican I were at their strongest. The State interfered whenever a Catholic Bishop disciplined a cleric for adhering to the Old Catholic sect; in several places, dismissed Old Catholic priests and even bishops were reinstated by the power of the State, similar to the manner in which the heretic emperors of old used to force the reinstatement of Arian bishops and priests.
In 1873, the Prussian Landtag passed the May Laws, which authorized the Old Catholics to establish themselves as a recognized Church and even contributed funding to help them in this purpose. The imperial Reichstag assisted this law by passing the Priests-Expulsion Law (Priester-ausweisungsgesetz), by which all priests deprived of their offices for violation of the May Laws were turned over to the discretion of the police authorities. Many bishops began to protest, and during 1873 Bismarck faced the first significant opposition to the Kulturkampf. Archbishops of Posen and Cologne and the Bishop of Trier were condemned to imprisonment; later, the Archbishop of Posen Count von Ledochowski, whose overtures to Bismarck in 1870 had precipitated the entire crisis, was deposed.
Following the May Laws and the subsequent episcopal protests, Falk's Ministry saw to it that all the Prussian episcopal sees were vacated. Many parishes were also deprived of their pastors, and most ecclesiastical educational institutions were closed. Bismarck had hoped that depositions would intimidate the Church, and that faced with the possibility of a total lack of Catholic ministry in whole regions, the Church would cave in and agree to state-appointed or authorized pastors. This was not to be, however. Cathedral chapters refused to select an administrator, and no parish consented to elect an "authorized" parish priest. The exiled bishops managed to govern their sees from abroad through secretly delegated priests. The faithful everywhere made it possible to hold Divine Services in the privacy of their homes, not unlike the faithful of England during the Elizabethan era of the "priest holes."
A civil marriage law of 1874 removed from priests the right oversight of sacrament of marriage by requiring German couples to engage in civil marriage before reception of the sacrament.
Assassination Attempt and Land Confiscations
In 1874, a man named Kullman, who had a very loose connection to a Catholic workingman's club, attempted to assassinate Bismarck. Bismarck was only slightly wounded in the hand, but he tried to link the attempt to the Catholic Centrum and paint the entire party with disloyalty to the State. In 1875 Bismarck suspended all state payments to the Prussian Catholic bishops, which had been guaranteed in the Prussian constitution. Later that year all Catholic monasteries were closed, except for those which cared for the sick.
Finally, in June, 1875, came the centerpiece of the anti-Catholic laws, the land confiscation. The Prussian Landtag passed a law which confiscated all the property of the Church, and turned over to its administration to lay trustees to be elected by the members of each parish. By the end of 1880, 1125 parish priests and 645 assistants had fallen victims to the new laws.
Catholic opposition was strong, with many favoring very radical resistance. The Association of German Catholics (Mainzer Verein), formerly a small group, ballooned 200,000 members, and became the bulwark of fierce opposition to the laws. Most of Europe regarded the laws as offensive to liberal sensibilities, save for the Kingdom of Italy, which was currently engaged in similar struggles against the Pope. The Centrum under Windthorst, meanwhile, struggled to reach some sort of compromise with the government to get the laws lightened. The Kulturkampf was alienating Austria, whose Hapsburg Emperor Francis Joseph was a very loyal Catholic and frowned on the efforts of Falk and Bismarck. The clergy of France and Belgium were unanimous in decrying the laws and encouraged German Catholics to resist them. Meanwhile, rank and file Catholics continued to disobey, priests continued to administer sacraments clandestinely, and bishops continue to administer their dioceses remotely.
The End of the Kulturkampf
The end of the Kulturkampf came ironically as a result of the same factor that had begun it: Bismarck's pragmatism. Bismarck had originally attacked the Church for a very practical political end: the weakening the Catholic Centrum. This had failed. By 1875-1878, political circumstances again changed and caused Bismarck to seek rapprochement with the Centrum for similar political reasons.
First, we could mention a war scare with France in 1875. It is beyond us to go into the details of that war scare here, but it is sufficient to note that the French clergy had been among the greatest supporters of the German clergy during the Kulturkampf. With a possible war looming, Bismarck needed all the support he could get on the side of the government, and hence was forced to reconcile with the Centrum to keep them from souring his preparations for a possible war with France.
Furthermore, the generation old Triple Alliance between Russia, Austria and Prussia broke down in 1878-79, leading to the new Dual Alliance between the German Empire and Austria. With Austria one of the most solidly Catholic countries in Europe, Bismarck found it necessary to lighten the restrictions of the Kulturkampf in order to avoid isolating Germany's new ally.
Furthermore, the Kulturkampf had led to an increase in the amount of deputies in the Reichstag and Landtag who were members of the Centrum. Ironically, the Centrum was stronger in 1879 than it had been in 1871. It could no longer be written off, and their numbers made it questionable whether any significant legislation could be passed without their support. Therefore, Bismarck needed to come to some kind of terms with them, but without losing face.
This opportunity came in 1878 with the death of Pope Pius IX. The election of Leo XIII established a sort of clean slate, and when the pontiff reached out to Kaiser Wilhelm upon his election, negotiations followed. Meanwhile, the conservatives, seeing the power of the Centrum, began to ally with the Catholic party. Falk was dismissed in 1879, and the most offensive laws of the Kulturkampf repealed by 1882. Bismarck balked at some of these developments, but with the advent of a strong Polish-Catholic nationalist movement in the preceding years, Bismarck saw clearly that the German Reich needed to be on friendly terms with the Church and became desirous of peace. There were many details to work out; most of the Kulturkampf laws were allowed to lapse; two laws of 21 May, 1886, and 29 April, 1887 formally ended the Kulturkampf by modifying or throwing out some of the most radical laws of 1873 and 1874.
Not all returned to the status quo, however. As mentioned above, the Jesuits remained banned until 1917. Not all property was returned. The Kanzelparagraf remained law until 1953, the civil marriage law of 1874 remains in effect to this day. Nevertheless, the Kulturkampf was one of Bismarck's greatest defeats; his fundamental misunderstanding of the cohesion of the Catholic hierarchy led him to vastly underestimate the resilience of the German Catholics. This is best summed up by the commentary of Odo Russell, the British diplomat in Berlin, who in 1874, wrote:
"The Roman Church has always derived strength from persecution...Bismarck's anti-Church policy has compelled the German bishops to rally around the Pope and to suffer martyrdom for discipline's, obedience's, and examples's sake." 
 Available online at: http://archive.org/stream/a628791400gladuoft#page/n3/mode/2up
 Erich Eyck, Bismarck and the German Empire (New York: The Norton Company: 1958), 204
 ibid., 205
 ibid., 208