Editing Unio Trium Nationum (section)

==Background==
===Medieval administrative structure in Transylvania===
[[File:Székely Land.PNG|300px|thumb|Territories of the Three Nations]]
[[File:Transylvania3states1700.jpg|300px|thumb|The territories of the Three Nations represented on a map made by [[Johann Homann]] in the first decades of the 18th century]]

In medieval times, Transylvania was organised into two separate types of territorial units: the Noble Counties ([[Comitatus (Kingdom of Hungary)|Comitates]]) were ruled by feudal landlords. Here, the majority of population were Hungarian and Romanian [[serfs]]. In other regions called [[Seat (territorial-administrative unit)|Seats]], the free [[Székelys|Székely]] and [[Transylvanian Saxons|Saxon]] nations lived without feudal landlords and had the royal privilege to have local authority and self-government.

===Events leading to the Union===
With the rise of the [[Ottoman Empire]], one of the first major Ottoman military campaigns against Transylvanian parts of the [[Kingdom of Hungary in the Middle Ages|Kingdom of Hungary]] was organised in 1421. The invading forces entered the region from [[Wallachia]]. The [[Transylvanian Saxons|Saxons]] and [[Székelys]] living in the border area tried to defend themselves, but were heavily outnumbered by the intruders. [[Sigismund, Holy Roman Emperor|King Sigismund]] was not able to react promptly because he had recently inherited the [[Bohemia|Bohemian throne]] and was involved there in the [[Hussite Wars]]. Also, Transylvanian Diets had not been organized for decades and there was no forum to coordinate defence preparations of the three nations. Left alone, the Saxon [[Burzenland]] and the Székely Seat of [[Háromszék]], both in the border region, were ravaged. Sigismund reacted to the attack only years later, leading a series of military campaigns against the Ottomans in Wallachia. The Ottomans, allied with the Wallachian Voivode, returned in 1432 and Southern Transylvania suffered serious damages again.

In the same period, nobles and church authorities in Central Transylvania were concerned about protesting and revolting [[serfs]]. [[Hungarian people|Hungarian]] and [[Romanians|Romanian]] ([[Vlach]]) peasants  were dissatisfied with high taxes and restrictions to their free movement. Scattered peasant protests turned into a serious revolt in 1437, when peasants and Hungarian nobles defeated the troops of the landholders. The [[Budai Nagy Antal Revolt]] was triggered by an attempt by the Bishop of Transylvania to collect taxes. Although the revolt was led by Hungarian noble [[Antal Nagy de Buda]], it consisted of a coalition of various elements of Transylvanian society. This included [[Hungarian people|Hungarian]] and [[Romanians|Romanian]] [[serfs]] as well as the burghers of [[Kolozsvár]] (''Klausenburg'', ''Cluj''), and resulted in the lower taxes codified by the Treaty of Kolozsmonostor. Pál Vajdaházi, one of the leaders of the revolt, was referred to in this document as ''{{lang|la|vexilifer Universitatis regnicolarum Hungarorum et Valachorum huius principatus Hungariae}}'' (Standard-bearer of the Union of Hungarian and Romanian inhabitants of this province of Hungary).  Consequently, it is possible that the rebels considered themselves inhabitants of the [[Estates of the realm|Estate]] of [[Hungarians]] and [[Romanians]] (''{{lang|la|Universitas Hungarorum et Valachorum}}'').{{Citation needed|date=February 2019}}

===Brotherly Union (Union of Kápolna)===
Despite the pressing issues at hand, the Transylvanian Diet was still not called together by the [[Voivode of Transylvania|Voivode]], resulting in the various nobles initiating a meeting of the three nations. After a gap of almost half a century, the estates now had the opportunity to discuss Transylvanian issues together. On this occasion, the nobles set up an alliance with [[Székelys]] and [[Transylvanian Saxons|Saxons]] who were still afraid of possible Ottoman incursions. The alliance of mutual aid, signed in Kápolna (present-day ([[Gâlgău|Căpâlna]]), was called the ''Fraterna Unio'' (Brotherly Union), and was designed to protect the parties both from revolts and Ottoman attacks. While the existence of the Union helped the indigenous inhabitants to re-negotiate and partly modify the terms of the previous agreement, the alliance did not organize any serious military operations until the end of 1437. At that time, the alliance defeated the opposition after the death of [[Sigismund, Holy Roman Emperor|King Sigismund]] in December.