Bohemia was the center of the Hussites, so why didn’t it accept a more prominent reform movement and instead remain Catholic?
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Well, the answer is is that they didn't remain Catholic, at least initially.
But, let's start with what the Hussites actually believed, at least in their initial incarnation. The basis of Hussite beliefs are best exemplified in what have become known as the Four Articles of Prague:
There's nothing terribly controversial or even un-Catholic about these points, on their face. The implementation of these points (especially amongst more radical sects of the Hussites, such as Žižka's Orphans and the Orebites), however, is where the largest points of disagreement existed. While the Utraquists, the largest and most influential Hussite sect, were much more moderate in their interpretation of these points, groups like the Orphans went much further – interpreting point four to mean something more along the lines of complete iconoclasm. Churches were stripped of their art, while priests in radical Hussite communities were forced to surrender their vestments and wear plain garments, even during the Mass itself. These radicals could even range as far as the Adamites, who gathered in large groups naked and believed that those engaged in monogamous marriage were barred from the Kingdom of Heaven (some sources allege that these large gatherings included orgies, however such sources also tended to be, perhaps unsurprisingly, less than complementary to these pre-modern nudists). In any case, while these radical sects existed, they tended to be smaller, and confined to various parts of the countryside (for example the Orphans mainly controlled the area of Tábor and surroundings). The moderate Utraquists, on the other hand, were centred in Prague, and, if one were pressed to make an anachronistic comparison, more akin to Anglicans than Lutherans – Catholic in all but unity and name.
With these divisions in mind, we turn to the political situation. After Hus' execution in 1415, the Hussites officially separated from the Catholic Church, leaving the political and religious situation in the Kingdom of Bohemia somewhat tenuous. Outright war between Catholic and Hussite factions was avoided by the King, Wenceslaus IV, who was somewhat sympathetic to the Hussites. With Wenceslaus' death in 1420, and the ascension of the very much Catholic King of Hungary, Sigismund, to the throne, however, war could no longer be avoided. To cut a somewhat long (and irrelevant to the question) story short, the Hussite movement initially fought as a unified front, repelling countless attempts by practically every neighbouring kingdom to quite literally crusade the Hussites, as well as internal Catholic resistance. In 1432, however, an exhausted Utraquist nobility switched sides, and swung their support behind Sigismund, and by 1434 the radical Hussites were put down. Meeting in Jihlava, the Hussites, Sigismund, and the Council of Basel (the Church's response to the Hussite movement) hammered out an agreement called the Compactata of Basel, which essentially guaranteed the right of Hussite priests to allow the taking of the Eucharist under both substances – the Body and Blood, the bread and the wine. This lasted right up until Pope Pius II nullified the Compacta in 1462, and offered the recognise the Hussite king, King Jiří z Poděbrad in exchange for a promise of "unconditional harmony" with the Catholic Church. King Jiří refused, and the relationship between the Bohemian Crown and Rome began to deteriorate, until Jiří's successor, King Vladislav II assented to Pope Pius II's demands. This, unsurprisingly, led to a rather uncomfortable situation within the Kingdom of Bohemia, which was resolved with a meeting of the Catholic and Hussite factions meeting at Kutná Hora in 1485 to conclude what has become known as The Religious Peace of Kutná Hora. The Religious Peace (Landfried) declared the Hussites and Catholics equal before the law for thirty-one years. In 1512, a Diet confirmed the Landfried, and the situation was relatively quiet up until
surprise
Martin Luther started a bit of a ruckus in Wittenberg, not very far over the Saxon border with Bohemia.
With the Reformation kicking off, many Hussites outright rejoined the Catholic Church, whilst others reorganised into what is today known as the Brethren. Others remained under the banner of Hussitism. By 1618, tensions had grown within Bohemia, and with the heirless Emperor Matthias II attempting to have his very, very Catholic brother Ferdinand elected to the Bohemian Crown, tensions grew further, boiling over when Ferdinand was elected King Ferdinand II of Bohemia, and sent two councillors to Prague Castle, who then got themselves promptly chucked out the window (shockingly, despite the 70 metre fall, all four men, including the two councillors, who were thrown out the window survived, by some accounts by virtue of being caught by an angel, and by others on account of having fallen into a dung heap).
This (Third) Defenestration of Prague (because chucking people out the window is a bit of a thing, I guess) kicked off what has become known as the Bohemian Revolt, and also sorta-kinda-totally kicked off the most destructive and disastrous conflict in European history right up until the First World War (and no, Napoléon doesn't even cut it close): the Thirty Years War. The Hussites and Lutherans appealed to the Protestant League for entrance, and determined that King Ferdinand II wasn't actually king after all (even though he was properly elected as king), and instead offered the throne to a variety of candidates (in what was practically a scam, as the Hussites and Lutherans were looking for an army to use to fight Ferdinand II, who by-the-way, was also the Holy Roman Emperor, and were offering up a product, the Crown, that they couldn't really deliver on). As it turns out, the young Elector of Palatine, Fredrick V, a devout Calvinist, fell for the bait, and accepted the post, leading an army into Bohemia, and getting whoppingly and decisively defeated at the Battle of Bílá Hora on 8. November 1620, having only entered Prague for the first time on 31. October 1619.
The Battle of Bílá Hora marked not only a disastrous defeat for the would-be King of Bohemia, Fredrick V, but also for the Hussite-Lutheran alliance in Bohemia. The anti-Catholic forces collapsed, and the victorious army proceeded to loot the countryside, whilst Emperor Ferdinand II confiscated thousands of properties from Bohemian, Hussite nobility and handed it over to German, Catholic nobility. The defeat of the Protestants in Bohemia marked the destruction of the longstanding power of the Bohemian Diet as well, essentially annexing Bohemia to the Imperial Crown directly.
With this open hand, the Emperor introduced the Counter-Reformation into Bohemia, which began a variety of reCatholicisation programmes (including one which taught the Catholic Faith to Bohemian peasantry through music, the effects of which led to the Bohemians being nicknamed the "Musical People", and would even later lead Mozart to comment that he much preferred Prague to Vienna, as the people there appreciated his music better). The Counter-Reformation was broadly successful, to the point that Hussitism became a dead movement in Bohemia, surviving only in small pockets in Moravia and expatriate communities in places like the Netherlands and Saxony.
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Short answer: It did, alongside Catholicism, until forced recatholization by Habsburgs since the beginning of the 30-Year War.
Long answer: The Hussite movement itself wasn't homogenous. There were multiple factions, some radical, some moderate. Some factions even fought each other. We need to mention at least two events here.
The battle of Lipany (1434). Radical Hussites led by Prokop the Great fought an alliance of moderate Hussites led by Diviš Bořek of Miletínek and Bohemian catholic forces. The defeat of the radicals opened way for the moderates to reach a diplomatic compromise with the catholics.
The Council of Basel–Ferrara–Florence (1431-1449). We are interested in the Basel phase which had multiple topics to solve. One topic was to find a diplomatic agreement with Hussite representatives, since no crusade was successful in defeating the Hussites. Before their defeat at the Battle of Lipany, the Hussite radicals were also present at the council. By 1436, diplomatic talks finally resulted in an agreement over the Hussite issue. The council issued the Compacts of Basel which agreed upon pretty much every important point of Hussite agenda and guaranteed freedom of faith for the moderates (later known as Utraquists).
The following years up until the end of 16th century were relatively calm when it comes to religion. Any tension between catholic and non-catholic representatives was solved through diplomacy with reference to Basel Compacts. Utraquists managed to keep their freedom of faith. The 2nd half of the 16th century is marked by Lutheran efforts to legalize their freedom of faith with a partial success - a promise of Maxmillian II. in 1575. No formal document was signed though.
At the beginning of the 17th century the non-catholic followers were predominant in the Lands of the Bohemian Crown and the religious scene was pretty diverse. There were lutherans here, calvinists, the then-banned Unity of the Brethren, etc. There was still no formal document to adress rights of other non-catholics apart from the utraquists and tensions grew in strength. In order to stabilize his rule, Rudolf II. issued The Letter of Majesty (1609) which guaranteed freedom of religion for catholics as well as non-catholics and adressed their relations. This solution didn't last long though. Since 1611 when Rudolf was forced to give up the Czech Crown in favour of his brother Matthias, tensions gradually arose again because Matthias intended to strenghten the position of catholics and pretty much didn't care about legal bindings of The Letter.
Ferdinand II. was elected by The Bohemian Diet to be the next Czech King in 1617 on condition that he would honour The Letter. Which, he did not intend to. Soon after the election, he took matters firmly in his hands despite Matthias, old and ill, still formally being the king of Bohemia until his death in 1619. This was one of major factors of why did the 30-Year War start in 1618 and not later.
All those previous tense years also mean that the Prague defenestration (1618) which sparked the 30-Year War was no random impulsive act. It was a thoroughly planned act and in the minds of the rebels it was even a rightful act in the tradition of earlier Bohemian defenestrations where law-trespassing officials were punished.
After the defeat of the non-catholic nobility at the Battle of White Mountain, Ferdinand II. sought to consolidate his power.
1627 (Bohemia) / 1628 (Moravia): The new constitution is published and forced into effect without required confirmation by The Bohemian Diet. Published fully in German under the name "Verneuerte Landesordnung". The Czech version wasn't even fully published. The new constitution was essentially a foundation stone of monoreligious absolutism and germanisation. Catholicism was not only promoted, Catholic Church representatives were also given much more power in The Bohemian Diet. Nobles in The Bohemian Diet, on the other hand, were severely limited in their voting power and royal cities were made almost voteless. German language was added as an official language in the Lands of the Bohemian Crown, formally equal to Czech, in practice though, German was made superior to Czech.
1627: Ferdinand II. issues a mandate that orders non-catholic nobles to either convert to catholicism within 6 months or to go into exile.