Zenovie Pâclișanu (1 May 1886 – 1957 or 1958) was an Austro-Hungarian-born Romanian historian, diplomat and cleric. A native of Transylvania, he completed a doctorate at Vienna, and during the 1910s was active in the cultural and religious life of Blaj. Following the creation of Greater Romania, which he enthusiastically supported, he became a civil servant, twice taking part in treaty negotiations. After World War II, the new communist regime suppressed his Greek-Catholic Church and threw Pâclișanu in prison, where he died. His work, banned under communism but partly re-edited in the years since, focuses on the history of Transylvania between the 17th and 19th centuries, particularly in the religious sphere.

Pâclișanu's research interests included ecclesiastical history, the Romanian national movement in Transylvania during the 18th century and the territorial revisionism of national minorities.^[1] His work on Transylvanian history from the 17th to the 19th century is important; he was an expert on the local Romanian church during the Reformation, interconfessional relations, the Romanian church hierarchy and the Enlightenment, and the national awakening of Transylvania's Romanians.^[2] Pâclișanu sought to move beyond confessional partisanship against the Romanian Orthodox Church, instead treating the history of the Greek-Catholic Church with a new methodology.^[9]

His publications include: Biserica și românismul. Studiu istoric (1910), the better known Vechile Mănăstiri Românești din Ardeal (1919), Alegerea Arhiereilor. Notițe istorice (1920), Propaganda catolică între românii din Ardeal și Ungaria înainte de 1500. Studiu istoric (1920), Din istoria bisericească a Românilor ardeleni. "Teologul" vlădicilor uniți (1700–1773). Studiu istoric cu anexe documentare (1923), Luptele politice ale Românilor ardeleni din anii 1790 – 1792. Studiu istoric cu anexe documentare (1923), Corespondența din exil a episcopului Inochentie Micu Klein, 1746 – 1768 (1924), Documente privitoare la istoria școalelor din Blaj (1930), Mișcările revizioniste în Statele europene în cursul anului 1931 (1932), Problema statutului minorităților (1935), Un vechi proces literar (Relațiile lui I. Bob cu S. Klein, Gh. Șincai și P. Maior) (1935), and Istoria creștinismului antic (1937). Following the cession of Northern Transylvania to Hungary imposed by the Second Vienna Award, his writings increased in frequency and virulence. He published works in German, Italian and French regarding Hungarian minority policy. Three late articles published in Revista Istorică Română retain their interest: "In jurul ierarhiei Românilor ardeleni în secolul XV" (1943), "Vechile districte românești de peste munți" (1943) and "Din corespondența doctorului Ioan Rațiu" (1944).^[8]

With the onset of the regime, Pâclișanu's work was banned in its entirety, and appeared only in fragmentary form in exile publications, particularly Catholic ones based at Rome.^[2] One of his wartime texts was published in the United States in 1985 as Hungary's Struggle to Annihilate its National Minorities. Based on Secret Hungarian Documents.^[8] He left in manuscript form the monumental church history Istoria Bisericii Române Unite, published only in 2006, as well as a lengthy series of studies. Although some historians began to cite his writings in more or less subversive manner after the slight cultural thaw in the early years of the Nicolae Ceaușescu era, his work never fully re-entered the academic mainstream. Nevertheless, a systematic attempt to recover his work began after the Romanian Revolution of 1989.^[2] Biserica și românismul was republished in 2005,^[8] while his doctoral thesis was printed in 2010, both in the Latin original and in a Romanian translation.^[2]