Origin of the title
The first known mention of the title ban is in the 10th century by Constantine VII Porphyrogenitus, in the work De Administrando Imperio, in the 30th and 31st chapter "Story of the province of Dalmatia" and "Of the Croats and of the country they now dwell in", dedicated to the Croats and the Croatian organisation of their medieval state. In the 30th chapter, describing how the Croatian state was divided into eleven ζουπανίας (zoupanias; župas), the ban βοάνος (Boanos), καὶ ὁ βοάνος αὐτῶν κρατεῖ (rules over) τὴν Κρίβασαν (Krbava), τὴν Λίτζαν (Lika) καὶ (and) τὴν Γουτζησκά (Gacka). In the 31st chapter, describing the military and naval force of Croatia, "Miroslav, who ruled for four years, was killed by the βοέάνου (boeanou) Πριβουνία (Pribounia, ie. Pribina)", and after that followed a temporary decrease in the military force of the Croatian Kingdom.
In 1029, was published a Latin charter by Jelena, sister of ban Godemir, in Obrovac, for donation to the monastery of St. Krševan in Zadar. In it she is introduced as "Ego Heleniza, soror Godemiri bani...". Franjo Rački noted that if it is not an original, then it is certainly a transcript from the same 11th century.
In the 12th century, the title was mentioned by Byzantine historian John Kinnamos, anonymous monk of
Dioclea, and in the Supetar Cartulary. The Byzantine historian John Kinnamos wrote the title in the form μπάνος (mpanos). In the Chronicle of the Priest of Duklja, which is dated to 12th and 13th century, in the Latin redaction is written as banus, banum, bano, and in the Croatian redaction only as ban. The Supetar Cartulary includes information until the 12th century, but the specific writing about bans is dated to the late 13th and early 14th century, a transcript of an older document. It mentions that there existed seven bans and they were elected by the six of twelve Croatian noble tribes, where the title is written as banus and bani.
The Late Proto-Slavic word *banъ is not of native Slavic lexical stock and is generally considered to be a borrowing from a Turkic language. The title's origin among medieval Croats is not completely understood, and as much is hard to determine the exact source and to reconstruct the primal form of the Turkic word it is derived from. It is generally explained as a derivation from the Pannonian Avars name
Bayan, which is a derivation of the Proto-Turkic root *bāj- "rich, richness, wealth; prince; husband". The Proto-Turkic root *bāj- is sometimes explained as a native Turkic word,; however, it is generally considered a borrowing from the Iranian bay (from Proto-Iranian *baga- "god; lord"). Within the Altaic theory, the Turkic word is inherited from the Proto-Altaic *bēǯu "numerous, great". The title word ban was also derived from the name Bojan, and there were additionally proposed Iranian,[nb 1] and Germanic,[nb 2] language origin.
The Avar nameword bajan, which some scholars trying to explain the title's origin interpreted with alleged meaning of "ruler of the horde", itself is attested as the 6th century name of Avar khagan Bayan I which led the raids on provinces of the Byzantine Empire. Some scholars assume that the name was a possible misinterpretation of a title, but Bayan already had a title of khagan, and the name, as well its derivation, are well confirmed. The title ban among the Avars has never been attested to in the historical sources, and as such the Avarian etymological derivation is unconvincing.
The title origin is unknown. It was used as "evidence" throughout the history of historiography to prove ideological assumptions on Avars, and specific theories on the origin of early medieval Croats. The starting point of the debate was year 1837, and the work of historian and philologist Pavel Jozef Šafárik, whose thesis has influenced generations of scholars. In his work Slovanské starožitnosti (1837), and later Slawische alterthümer (1843) and Geschichte der südslawischen Literatur (1864), was the first to connect the ruler title of ban, obviously not of Slavic lexical stook, which ruled over župas of today Lika region, with the Pannonian Avars. He concluded how Avars lived in that same territory, basing his thesis on a literal reading of the statement from Constantine VII's 30th chapter, "there are still descendants of the Avars in Croatia, and are recognized as Avars". However, modern historians and archaeologists until now proved the opposite, that Avars never lived in Dalmatia proper (including Lika), and that statement occurred somewhere in Pannonia. Šafárik assumed that the Avars by the name word bayan called their governor, and in the end concluded that the title ban derives from the "name-title" Bayan, which is also a Persian title word (see Turkish bey for Persian bag/bay), and neglected that it should derive from the Slavic name Bojan. His thesis would be later endorsed by many historians, and both South Slavic titles ban and župan were asserted as Avars official titles, but it had more to do with the scholar's ideology of the time than actual reality.
Franz Miklosich wrote that the word, of Croatian origin, probably was expanded by the Croats among the Bulgarians and Serbs, while if it is Persian, than among Slavs is borrowed from the Turks. Erich Berneker wrote that became by contraction from bojan, which was borrowed from Mongolian-Turkic bajan ("rich, wealthy"), and noted Bajan is a personal name among Mongols, Avars, Bulgars, Altaic Tatars, and Kirghiz. Đuro Daničić decided for an intermediate solution; by origin is Avar or Persian from bajan (duke).
J. B. Bury derived the title from the name of Avar khagan Bayan I, and Bulgarian khagan Kubrat's son Batbayan, with which tried to prove the Bulgarian-Avar (Turkic) theory on the origin of early medieval Croats. Historian Franjo Rački didn't discard the possibility South Slavs could obtain it from Avars, but he disbelieved it had happened in Dalmatia, yet somewhere in Pannonia, and noticed the existence of bân ("dux, custos") in Persian language. Tadija Smičiklas and Vatroslav Jagić thought that the title should not derive from bajan, but from bojan, as thus how it is written in the Greek historical records (boan, boean).
Vjekoslav Klaić pointed out that the title before 12th century is only among Croats documented, and did not consider a problem that Bajan was a personal name and not a title, as seen in the most accepted derivation of Slavic word *korljь (kral/lj, krol). He mentioned both thesis (from Turkic-Persian, and Slavic "bojan, bojarin"), as well the German-Gothic theory derivation from banner and power of ban and King's ban. Gjuro Szabo shared similar Klaić's viewpoint, and emphasized the widespread distribution of a toponym from India to Ireland, and particurarly among Slavic lands, and considered it as an impossibility that had derived from a personal name of a poorly known khagan, yet from a prehistoric word Ban or Fan.
Ferdo Šišić considered that is impossible it directly originated from a personal name of an Avar ruler because the title needs a logical continuity. He doubted its existence among Slavic tribes during the great migration, and within early South Slavic principalities. He strongly supported the Šafárik thesis about Avar descendants in Lika, now dismissed by scholars, and concluded that in that territory they had a separate governor whom they called bajan, from which after Avar assimilation, became Croatian title ban. The thesis of alleged Avar governor title Šišić based on his personal derivation of bajan from the title khagan. Nada Klaić advocated the same claims of Avars descendants in Lika, and considered bans and župans as Avar officials and governors.
The latter conclusion by Šišić and Klaić was previously loosely opposed by Rački, who studying old historical records observed that ban could only be someone from one of the twelve Croatian tribes according to Supetar cartulary. This viewpoint is supported by the Chronicle of Duklja; Latin redaction; Unaquaque in provincia banum ordinavit, id est ducem, ex suis consanguineis fratribus ([Svatopluk] in every province allocated a ban, and they were duke's consanguin brothers); Croatian redaction defines that all bans need to be by origin native and noble.
The mainstream view of the time was mainly opposed by Stjepan Krizin Sakač, who emphasized that the word bajan is never mentioned in historical sources as a title, the title ban is never mentioned in such a form, and there's no evidence that Avars and Turks ever used a title closely related to the title ban. Sakač connected the Croatian bân with statements from two Persian dictionaries (released 1893 and 1903); the noun bàn (lord, master, illustrious man, chief), suffix bân (guard), and the Sasanian title merz-bân (مرزبان marz-bān, Marzban). He considered that the early Croats originated from the Iranian-speaking Sarmatians and Alans. The view of the possible Iranian origin (from ban; keeper, guard), besides Avarian, was shared by the modern scholars like Vladimir Košćak, Horace Lunt and Tibor Živković.
In the 21st century, historian Mladen Ančić (2013) noted that the Avar linguistic argumentation is unconvincing and the historical sources poorly support such a thesis. He emphasized that such a consideration is related to cultural and political ideologization since the 19th century which avoided any association with Germanization and German heritage. According to him, the title and its functions directly derive from a Germanic medieval term ban or bannum, the royal power of raising of armies and the exercise of justice later delegated to the counts, which was widely used in Francia. Archaeologist Vladimir Sokol (2007) independently came to a very similar conclusion relating it to the influence of Franks during their control of Istria and Liburnia. In 2013, historian Tomislav Bali noted the possible connection of the title with the military and territorial administrative unit bandon of the Byzantine Empire. The unit term derives, like the Greek bandon (from the 6th century) and Latin bandus and bandum (from the 9th century; banner), from the Gothic bandwō, a military term used by the troops who had Germanic or fought against Germanic peoples. Bali considered that the Croatian rulers possibly were influenced by the Byzantine model in the organization of the territory and borrowed the terminology and that such thesis can be related to Sokol's arguing of Western influence.