Universitas Valachorum (Estate of the Vlachs) is the Latin denomination for an Estate, an institution of self-government of the Romanians in medieval Transylvania, which then belonged to the Kingdom of Hungary.
The structure of the Universitas Valachorum placed the leadership of common Romanians upon their own nobility (Voivodes, Knez), enjoying a jurisdiction based on their own laws (Jus Valachicum). In the face of external danger such as Tatars, Cumans, Saracens and other pagans (omnino Tartarorum vel Cumanum Saracenum vel Meugarium) the Universitas of Romanians was called together with the other Estates of Transylvania (universisque nobilibus Ungarorum, Saxonibus, Syculis et Volachis) to defend Christian faith, according to the letter of Lodomer, Archbishop of Esztergom in 1288.
When summoned by the king or the voivod to the general assembly of Transylvania (congregatio generalis), Universitas Valachorum attended the assembly together with the other three Estates of Transylvania: Nobility, Saxons, and Székelys (Universis nobilibus, Saxonibus, Syculis et Olachis in partibus Transiluanis - András III summoning the assembly of Estates of Transylvania that took place on 22 February 1291).
After the formation of Wallachia in 1330 the former Universitas Valachorum was separated in two parts. Those from ultra Alpes in terram Basarab formed the independent ruling class of Wallachia while the Romanians from Transylvania gradually lost their status as an Estate and were excluded from Transylvania's assemblies.
In the year 1366, king Louis I Anjou of Hungary issued a law-and-order Decree of Turda in part explicitly targeted against the Romanians (presumptuosam astuciam diversorum malefactorum, specialiter Olachorum1, in ipsa terra nostra existencium - the evil arts of many malefactors, especially Vlachs /Romanians that live in that our country; exterminandum seu delendum in ipsa terra malefactores quarumlibet nacionum, signanter Olachorum - to expel or exterminate from this country malefactors belonging to any nation, especially Vlachs/Romanians). Through the same decree, nobility (nobilis Hungarus) is partially redefined in terms of adherence to the Roman Catholic Church, thus excluding the Eastern Orthodox schismatic Romanians. The main reason for this policy was of political and religious nature: during Louis I's proselytizing campaign, privileged status was deemed incompatible with that of schismatic Eastern Orthodoxy in a state endowed with an apostolic mission by the Holy See.
Another consequence of the decree was socio-economic: the status of nobleman was determined not only by ownership over land and people, but (from 1366 on) by the possession of a royal donation certificate for the land owned. The Romanian social elite, chiefly made up of aldermen (iudices or knezes), managed to procure few writs of donation; they had ruled over their villages according to the old law of the land (ius valachicum, with its feudal version, ius keneziale); their lands were, to a great extent, expropriated. Lacking a recognized title to real property, the Eastern Orthodox Romanian elite was not able any more to maintain an Estate of their own and to participate in the country's assemblies.
Insofar as a Romanian elite was preserved, it adjusted to these circumstances by converting to Roman Catholicism and being absorbed into Hungarian Catholic aristocratic estate (nobilis Hungarus). Those Romanian knezes (and voivods) who did not convert and could not gain the desired privileges gradually declined into the ranks of subjects or even bondsmen.
The last page of the history of Universitas Valachorum was written in 1437, as Transylvania witnessed the official establishment of the "brotherly union" or fraterna unio Unio Trium Nationum, that is, a community or gathering (universitas) of nobles, Saxons and Székelys, with the view of defending the country against the Ottoman threat and the inner danger of rebellious peasants. The adoption of the Unio Trium Nationum, which implicitly excluded the Estate of Romanians, gave constitutional sanction to the end of the Universitas Valachorum.
- Müller Friedrich: Haben 1288 im Hermannstadter Gau und im Burzenland neben den Sachsen auch ungarische Adlige, Szekler und Rumänen gewohnt?, Siebenbürgische Vierteljahrschrift, Hermannstadt, 58/1935 Nr 4, pp.281-296 
- Köpeczi Béla, Barta Gábor, Bóna István, Makkai László, Szász Zoltán, et al., Kurze Geschichte Siebenbürgens, Akadémiai Kiadó, Budapest, 1989, p.195 
- Pop I.-A., L’assemblée générale des Etats de Transylvanie de mai 1355, Transylvanian Review, IX, 2000, pp. 36 - 45
- Dani I., Gündish K. et al. (eds.), Documenta Romaniae Historica, Series C, Transilvania, vol.XIII (1366-1370), Bucarest, 1994, p. 161 - 162
- Binder Pál, South-transylvanian antecedents and consequences of the formation of the Principality Muntenia, Századok, Budapest, 1995/5 
- Pop I.-A., Instituţii medivale româneşti. Adunări cneziale şi nobiliare în secolele XIV XVI, Cluj-Napoca, 1991, pp. 9 – 26
- Pop I.-A., Nations and Denominations in Transylvania (13th - 16th Century) p. 111 - 125, In Tolerance and Intolerance in Historical Perspective, edited by Csaba Lévai et al., Edizioni PLUS, Università di Pisa, 2003