Religion has always been important to the Poles. They have used it to define their identity and to construct a national mythology, projecting to the outside world the image of a nation more bound up with its religion than any other, devoted to its practice and motivated by its orthodoxy. The reality is somewhat different. However deep and lasting the influence of religion may have been on the Poles, it has never dominated their judgments or their instincts to the extent that it has those of other nations which hardly qualify as particularly spiritual or bigoted.
A significant proportion of the population was not Christian at all. The Jewish community multiplied each time there was an anti-Semitic witch-hunt in other countries, and its numbers soared in the decades after the expulsions from Spain in 1492 and Portugal in 1496. If zealous prelates were shocked to see synagogues in every Polish township, they were hardly less so to see mosques standing on what was supposed to be Christian soil. These belonged to the descendants of Tatars who had settled in Lithuania in the fifteenth century and become loyal subjects of their adopted country. Many of them had been admitted to the ranks of the szlachta, but clung to the Islamic faith.
One of the conditions of the Union between Poland and Lithuania in 1385 had been the immediate conversion of that country to Christianity but by the mid-sixteenth century there were nearly a hundred mosques in the Union. The Polish hierarchy had failed to impose a strict Catholic or even Christian orthodoxy on the population, largely on account of its personal and political viewpoint. The Polish Church enjoyed a unique relationship with the Vatican. Its bishops were appointed not by Rome but by the King of Poland, who submitted his candidates for Rome's approval.
One searches in vain for ardent spiritual involvement or preoccupation with dogma in the Polish religious tradition. It was remarkable immune to the crises that convulsed the Church in other countries - the great heresies of the twelfth and thirteenth centuries, and the reaction to the Black Death, whose horrors seemed to negate the existence of a benevolent God. The only major heresy which did affect Poland, the Hussite movement, did so because it was not so much a heresy as a political movement.
In view of all this, it is not surprising that when Martin Luther nailed his famous declaration of war on the Papacy to the church door in 1517 and set off a chain reaction which was to shake the whole Christian world, the seismic nature of the event was largely lost on Poland. His teaching rapidly penetrated northern and western areas only, enthusiastically received by the preponderantly German population of the towns. Calvinism was another matter. Enhanced by its more sympathetic Francophone association, it rapidly gained ground all over the country. The democratic spirit of Calvinism which placed the lay elder on a par with the minister could hardly fail to appeal to the instincts of the szlachta, while the absence of pomp and ceremony from its rites made it a pleasantly cheap religion to support. By the 1550s a dominant proportion of the deputies to the Seym (Parliament) were Protestants, but their number is not representative, since the most ardently Catholic palatinates regularly returned Protestant deputies. By 1572 the Senate provided a similar picture.
The large Jewish community in Poland had also been affected by the spirit of the times, and the expulsions from the Iberian peninsula had brought many distinguished scholars to Poland. In 1567 a Talmudic Academy was founded in Lublin. This added a new dimension to the religious debate raging throughout the country. The Jews themselves were not united, and there were still considerable colonies of Karaites, Jews who accepted only the Bible and rejected the Talmud. The Arians made many converts from the ranks of Talmudic Jews, while a number of Arians and Calvinists converted to Judaism.
Luther's revolt released passionate feelings among the clergy. Apart from the practical demands, it aroused a general revulsion against the medieval obscurantism of the Church. King Zygmund the Old (1506-48) felt that the religious debate was none of his business. He came under considerable pressure from Rome and from those of his bishops who were in favor of stamping out the heresy. He was even reproached by King of England for not taking a more energetic line against the Protestants. Whenever this pressure became very strong, he would take some action to satisfy the zealots, but his edicts were not worth the paper they were written on without the approval of the Seym. All were agreed that there would be no liberty while the ecclesiastical courts which were independent of the parliamentary system were able to judge people and sentence them for any reason. Their jurisdiction was annulled by act of the Seym in 1562.
The Reformation in Poland was not at bottom a spiritual movement. It was a sally by the articulate classes who made use of the liberating challenge of Luther to further a process of intellectual and political emancipation which had started long before. The szlachta which had done everything to curtail the power of the crown seized eagerly on the possibilities offered by the movement for reform in order to break the power of the Church. Straightforward anticlericalism was easily confused with a desire for a return to true Christian principles, and so was another movement in Polish politics which reached a climax in the 1550s.
The executionist movement was intellectually and temperamentally the sibling of the Protestant movement, and it attracted much of the zeal which might otherwise have been concentrated on religious questions. At the same time, Catholic voters elected Calvinist deputies because they were executionists, and Catholic deputies voted with the executionist Calvinists on issues such as the demand for a national Church, on the abolition of ecclesiastical tribunals, and on the law forcing the Church to contribute financially to defense. Even at the height of the Reformation no Pole, be he a Catholic, a Lutheran, a Calvinist or an Arian, was prepared to place religious issues before constitutional and legal ones. This is why the Reformation failed in Poland.
The Catholic Church, which had dodged the heaviest blows and avoided confrontation, slowly went over to the offensive, as the Counter-Reformation gained strength. In Poland its progress was unsensational: no inquisition, no anathemas, no religious terrorism, no forfeitures of property, no barring from office - none of the features normally associated with the Counter-Reformation in the rest of Europe. It could hardly have been otherwise, given the spirit of legality and humanism pervading Polish society.
With the impending extinction of the Jagiellon dynasty, Poland and Lithuania needed unity of purpose rather than dissent and refusal to take responsibility. Nevertheless, the constitutional and legal aspects of the case were still paramount. After the death of Zygmund Augusts the Seym which met under the name of the Confederation of Warsaw to shape Poland's future in 1573 passed an Act whose most memorable clause ran as follows: "we will keep the peace between ourselves, and that we will not, for the sake of our various faith and difference of church, either shed blood or confiscate property, deny favor, imprison or banish, and that furthermore we will not aid or abet any power or office which strives to this in any way whatsoever…". The freedom to practice any religion without suffering discrimination or penalty was henceforth enshrined in the constitution.

Excerpts from the book "The Polish Way" by Adam Zamojski
(John Murray-Publishers Ltd. London 1987)