Io (Church Slavonic: Ιω, Їѡ and Иѡ, also Iωан and Iωнь; Romanian Cyrillic: Iѡ; ) is the contraction of a title used mainly by the royalty (hospodars or voivodes) in Moldavia and Wallachia, preceding their names and the complete list of titles. First used by the Asenid rulers of the Second Bulgarian Empire, the particle is the abbreviation of theophoric name Ioan (John), which comes from the original Hebrew Yohanan, meaning "God has favored". Io appeared in most documents (written or engraved), as issued by their respective chancelleries, since the countries' early history, but its frequency and relative importance among the princely attributes varied over time. Its usage probably dates back to the foundation of Wallachia, though it spread to Moldavia only in the 15th century. In more informal contexts, Romanians occasionally applied the title to benefactors or lieges from outiside the two countries, including John Hunyadi and George II Rákóczi.

Initially used with Slavonic and Latin versions of documents, the word increasingly appeared in Romanian-language ones after 1600. With time, the Wallachian Io also came to be used by some women of the princely household, including Elena Năsturel and Doamna Marica. The arrival of the Phanariotes as rulers in both countries also ended the practice of avoiding the name "John" for Princes, and created duplications of the original styling, as "Io John". As it entered more general use and its meaning was obscured, the title was gradually confounded with the first-person pronoun, Eu, and alternated with the royal we, Noi, until being finally replaced by it in the 19th century. With the rise of modern historiography, Ios meaning and origin became entangled in lasting scholarly disputes. A final attempt to revive it for Carol as Domnitor of the United Principalities was made by Alexandru Papiu Ilarian in 1866.

History Early usage The ultimate origin of Io is with the Biblical Yohanan (), a reference to the divine right, and, in the baptismal name "John", an implicit expression of thanks for the child's birth; the abbreviation is performed as with other nomina sacra, but appears as Ioan in Orthodox Church ectenia.Croitoru, pp. 392–394, 406 The Slavonic Ιω very often features a tilde over the second letter, which is indicative of a silent "n".Xenopol, p. 147 Io is therefore described by scholar Emil Vârtosu as "both name and title".Gorovei (2005), p. 45 Its connection to the name "John", and its vocalization as Ioan, are explicitly mentioned by Paul of Aleppo, who visited Wallachia in the 1650s. However, he provides no explanation for why this particular name was favored.Croitoru, p. 406 Historian Radu G. Păun describes it specifically as a "theophoric name", which "served to highlight that princely power derives directly from God and not from an intermediary agency".Radu G. Păun, "Încoronarea în Țara Românească și Moldova în secolul al XVIII-lea. Principii, atitudini, simboluri", in Revista Istorică, Vol. 5, Issues 7–8, 1994, p. 745 Theologian Ion Croitoru argues that Io placed Wallachian and Moldavian Princes under the patronage of John the Evangelist, and that it doubles as a reference to their status as defenders of the Orthodox faith.Croitoru, pp. 392–394

The intermediate origin of Io is the Second Bulgarian Empire (1185–1396), located just south of early medieval territories which became Wallachia and Moldavia. As noted by historian A. D. Xenopol, it honors Ivan I Asen, in line with titles such as Caesar and Augustus. He also makes note of its standardized usage by later Asenids, as with the Gospels of Tsar Ivan Alexander (1355–1356). Xenopol sees the Asenid empire as partly Vlach, and therefore proto-Romanian, but rejects the claim that it ever ruled territories in either Moldavia or Wallachia.Xenopol, pp. 223–230 Slavist Ioan Bogdan similarly describes Io as borrowed from the Asenids "by diplomatic and paleographic means [...], first in documents, as an imitation of Bulgarian documents, then in other written monuments".Mihăilă, p. 274 The same Bogdan hypothesizes that the title was borrowed in a Moldo–Wallachian context as a posthumous homage to the first Asen rulers, while Nicolae Iorga sees it as a Vlach title which existed in both lands; archivist Damian P. Bogdan suggests a third option, namely that Io was originally a Medieval Greek title used in the Byzantine Empire—a contraction of Ἱωάννης, as used for instance by John II Komnenos and John V Palaiologos.Damian P. Bogdan, "Notițe bibliografice. Dölger Franz, Facsimiles byzantinischer Kaiserurkunden", in Revista Istorică Română, Vol. III, Parts II–III, 1933, p. 290 This position is also taken by historian Ion Nistor, who believes that Ivan Asen left no document to attest his signature.Nistor, p. 149 Other scholars, beginning with Marin Tadin in 1977, argue that, though widely understood and vocalized as "John", Io was originally a misunderstanding replicated by Bulgarian and Wallachian scribes alike. They trace its origin to the Slavonic phrase въ I[мѧ] Ѡ[тъца]—"In the name of the Father".Dionysopoulos, pp. 210–211

During Moldavia and Wallachia's early history, the court language was Church Slavonic, using Early Cyrillic. Early adaptations of Io may date back to Wallachia's creation as an independent polity: as noted by Nistor, Basarab I was known in neighboring Serbia as Ivanko, and therefore "John". Numismatist Traian Bița endorsed this interpretation by noting that some period coinage, mysteriously minted by a Prince only known as IWAN, may be Basarab's own issue.Bița (2001), pp. 174–176 Similarly, historian A. Stănilă argues that it was Basarab himself who adopted the title as an homage to the Asenids, which included his in-law Ivan Alexander. He also proposes that IO can be read as an acronym for the Renaissance Latin Iohannes Onores ("In honor of John").Stănilă, p. 63

The claim according to which Ivanko was the same as Basarab remains disputed by other scholars, who believe that it may refer to one of his descendants from the "House of Basarab"—either a poorly attested "John Basarab" (possibly Thocomerius) or Basarab's documented son and successor, Nicholas Alexander.Bița (2001), pp. 170–176 Any explicit use of Io remains unattested until 1364, when it is included on Nicholas Alexander' epitaph, who (as Nistor notes) may have been directly inspired by the monogram of John Palaiologos. In the 1370s, Vladislav I began using Io in his signature—though never as an introductory formula on his edicts. He also minted coins with inscriptions in either Latin or Slavonic. Only the latter carry variants of Io—Ιω and Iωан; the Latin ones make no such provision.Bița (2001), pp. 169, 172–173; Moisil, pp. 133–135, 139; Stănilă, pp. 72–73 Under Vladislav's brother and successor Radu I, coins in Latin began featuring IONS as a translation of Ιω and contraction of Iohannes.Moisil, pp. 136, 148. See also Stănilă, p. 73

A trove of coins dating back to the rule of Mircea the Elder (1386–1394, 1397–1418) uses IWAN for IONS.Bița (2001), passim; Moisil, p. 418 Bița notes that these were found alongside coins only mentioning IWAN, and hypothesizes that they refer to Ivanko Dobrotitsa, the last man to ruler over the Dobrujan Despotate. The Despotate is generally assumed to have fallen to Mircea's invasion in 1411, with Ivanko being killed in the field of battle; Bița hypothesizes that this invasion ended with an understanding between Mircea and the Dobrujans, and that Ivanko may have survived as Mircea's co-ruler in the region.Bița (2001), pp. 178–180 Mircea was also the first Wallachian to use Io in both his introductory formula and his signature, a practice also taken up by his son Michael I.

Mircea's enemy, Vlad I, who took the throne in 1396, was the first to use a Slavonic Io on Wallachia's Greater Seal version (featuring the Wallachian eagle or raven). Upon his return, Mircea added Slavonic Io on his Smaller Seal version—which, unusually, featured a lion rampant rather than the bird. The seal, used only once in 1411, reads †Iѡ Мирча Велики Воевода ("Io Mircea, Great Voivode").Tiron, pp. 520, 522, 525, 544, 546, 549 With Latin still in high favor, a Slavonic Io was again added to the Greater Seal by Vladislav II in 1451.Tiron, pp. 522, 546 A version also appears in the Commentaries of Pope Pius II, which render Vlad the Impaler's 1462 letter to Mehmed the Conqueror in Latin translation. The Slavonic original, whereby Vlad places Wallachia under Ottoman vassalage, is presumed lost; in this surviving version, Vlad's name is omitted, possibly by mistake, and the text is left with "Io Voivode, Prince of Wallachia".Lucian Constantin Palade, "Vlad Țepeș și Înalta Poartă", in Argesis. Studii și Comunicări. Seria Istorie, Vol. XXIII, 2014, p. 73

Spread Io entered usage in Moldavia only after it became established in Wallachia. Moldavia's first coin series were all-Latin, and did not use any variant of Io,Bița (1997), pp. 194–197 though it was attested by other documentary sources, including the full titles of Roman I. This historical record is also noted for including references to the Eastern Carpathians and the Black Sea, which various historians read as a clue that, by 1390, Moldavia had ended its expansion.Gheorghe Brătianu, "În jurul întemeierii statelor românești (III)", in Revista Istorică, Vol. 4, 1993, p. 596; Igor Cașu, Virgil Pâslariuc, "Chestiunea revizuirii hotarelor RSS Moldovenești: de la proiectul 'Moldova Mare' la proiectul 'Basarabia Mare' și cauzele eșecului acestora (decembrie 1943 – iunie 1946)", in Archiva Moldaviæ, Vol. II, 2010, pp. 312, 349 Io also showed up in other texts of that era, as with the 1429 Gospels "from the time of our honorable and Christ-loving Prince Io Alexander Voivode".Lupu (2017), p. 3 The same Alexander used the particle more rarely than his contemporaries, except on a stole which he donated to the monastery of Staraya Ladoga. Its embroidered text shows the Greek version of Io, additionally calling Alexander "Autokrator of Moldowallachia".Nistor, pp. 149, 277–278

On various other documents, Io alternated with a Slavonic form of the royal we: Мꙑ. As noted by historian Ștefan S. Gorovei, Moldavia's Stephen the Great (reigned 1457–1504) introduced himself using both Ιω (or Iωан) and Мꙑ. The former is always present on stone-carved dedications made by Stephen, and on his version of the Greater Moldavian Seal, but much less so on the Smaller Seal.Gorovei (2005), p. 48. See also Nistor, p. 149 It also appears in the unusual reference to Stephen as Tsar (царъ) of Moldowallachia, as found on his illuminated Gospel at Humor Monastery (1473).Nastase, pp. 69, 94–95 Io on its own was present on Stephen's church bell at Bistrița Monastery; some reports suggest a similar Io-inscribed bell once existed at Neamț.Chiaburu, pp. 31–31 On only three occasions, the two words were merged into Мꙑ Ιω or Мꙑ Iωан; one of these is a 1499 treaty which also carries the Latin translation, Nos Johannes Stephanus wayvoda.Gorovei (2005), pp. 45–48 According to Gorovei, it is also technically possible that Stephen's Romanian name was vocalized by his boyars as Ioan Ștefan voievod, since the corresponding Slavonic formula appears in one document not issued by Stephen's own chancellery.Gorovei (2005), pp. 47–48. See also Lupu (2017), p. 7 A standalone Ιω was also used by Stephen's son and one-time co-ruler Alexandru "Sandrin", and appears as such on his princely villa in Bacău.Ilie, p. 88 It makes its first appearance on coins under Bogdan the Blind—who was Stephen's other son and his immediate successor.Bița (1997), pp. 196–197