Knyaz or knez is a historical Slavic title, used both as a royal and noble title in different times of history and different ancient Slavic lands. It is usually translated into English as prince, duke or count, depending on specific historical context and the potentially known Latin equivalents of the title for each bearer of the name. In Latin sources the title is usually translated as comes or princeps, but the word was originally derived from the Proto-Germanic *kuningaz (king).
The female form transliterated from Bulgarian and Russian is knyaginya (?), kneginja in Slovene and Serbo-Croatian (Serbian Cyrillic: ?). In Russian, the daughter of a knyaz is knyazhna (). In Russian, the son of a knyaz is knyazhich ( in its old form).
The title is pronounced and written similarly in different European languages. In Serbo-Croatian and some West Slavic languages, the word has later come to denote "lord", and in Czech, Polish and Slovak also came to mean "priest" (kn?z, ksi?dz, k?az) as well as "duke" (knez, kní?e, ksi, knie?a). In Sorbian it means simply "Mister" (from "Master". Compare French monsieur from mon sieur "my lord"). Today the term knez is still used as the most common translation of "prince" in Bosnian, Croatian and Serbian literature. Knez is also found as a surname in former Yugoslavia.
The etymology is ultimately a cognate of the English king, the German König, and the Swedish konung. The proto-Slavic form was , k?n?dz?;Church Slavonic: ,k?n?dz?; Bulgarian: ?, knyaz; Old East Slavic: , knyaz?; Polish: ksi; Serbo-Croatian: knez, ?; Czech: kní?e; Slovak: knie?a; etc., as it could be a very early borrowing from the already extinct Proto-Germanic Kuningaz, a form also borrowed by Finnish and Estonian (kuningas).
The meaning of the term changed over the course of history. Initially the term was used to denote the chieftain of a Slavic tribe. Later, with the development of feudal statehood, it became the title of a ruler of a state, and among East Slavs (Russian: (kniazhestvo), Ukrainian: ? (knyazivstvo) traditionally translated as duchy or principality), for example, of Kievan Rus'. In medieval Latin sources the title was rendered as either rex or dux. In Bulgaria, Boris I of Bulgaria changed his title to knyaz after his conversion to Christianity, but his son Simeon took the higher title of tsar soon in 913. In Kievan Rus', as the degree of centralization grew, the ruler acquired the title Velikii Knyaz (? ) (translated as Grand Prince or Grand Duke, see Russian Grand Dukes). He ruled a Velyke Knyazivstvo ( ?i?c) (Grand Duchy), while a ruler of its vassal constituent (udel, udelnoe knyazivstvo or volost) was called udelny knyaz or simply knyaz.
When Kievan Rus' became fragmented in the 13th century, the title Kniaz continued to be used in East Slavic states, including Kiev, Chernihiv, Novgorod, Pereiaslav, Vladimir-Suzdal', Muscovy, Tver, Halych-Volynia, and in the Grand Duchy of Lithuania.
As the Tsardom of Russia gained dominion over much of former Kievan Rus', Velikii Kniaz (? ) (Great Kniaz) Ivan IV of Russia in 1547 was crowned as Tsar. From the mid-18th century onwards, the title Velikii Kniaz was revived to refer to (male-line) sons and grandsons of Russian Emperors. See titles for Tsar's family for details.
Kniaz (Russian: , IPA: ['kn?æs?]) continued as a hereditary title of Russian nobility patrilineally descended from Rurik (e.g., Belozersky, Belosselsky-Belozersky, Repnin, Gorchakov) or Gediminas (e.g., Galitzine, Troubetzkoy). Members of Rurikid or Gedyminid families were called princes when they ruled tiny quasi-sovereign medieval principalities. After their demesnes were absorbed by Muscovy, they settled at the Moscow court and were authorised to continue with their princely titles.
From the 18th century onwards, the title was occasionally granted by the Tsar, for the first time by Peter the Great to his associate Alexander Menshikov, and then by Catherine the Great to her lover Grigory Potemkin. After 1801, with the incorporation of Georgia into the Russian Empire, various titles of numerous local nobles were controversially rendered in Russian as "kniazes". Similarly, many petty Tatar nobles asserted their right to style themselves "kniazes" because they descended from Genghis Khan.
See also "Velikiy Knyaz" article for more details.
Finally, within the Russian Empire of 1809-1917, Finland was officially called Grand Principality of Finland (fi Suomen suuriruhtinaskunta, sv Storfurstendömet Finland, ru Velikoye Knyazhestvo Finlyandskoye).
As noted above, the title knyaz or kniaz became a hereditary noble title in the Grand Duchy of Moscow and the Grand Duchy of Lithuania. Following the union of the Kingdom of Poland and the Grand Duchy of Lithuania, knia? became a recognised title in the Polish-Lithuanian Commonwealth. By the 1630s - apart from the title pan, which indicated membership of the large szlachta noble class - knia? was the only hereditary title that was officially recognised and officially used in the Polish-Lithuanian Commonwealth. Notable holders of the title knia? include Jeremi Wi?niowiecki.
In the 19th century, the Serbian term knez (?) and the Bulgarian term knyaz (?) were revived to denote semi-independent rulers of those countries, such as Alexander Kara?or?evi? and Alexander of Battenberg. In parts of Serbia and western Bulgaria, knez was the informal title of the elder or mayor of a village or zadruga until around the 19th century. Those are officially called ? (gradona?elnik) (Serbia) and ? (gradonachalnik) or ? (kmet) (Bulgaria).
In medieval Bosnia knez was title held by several of most powerful magnates (in Bosnia vlastelin) of the era, sometime along with an office title given to person through service to the monarch, such as Grand Duke of Bosnia, which was office of the supreme military commander of the realm. Other noble titles included the count, the duke and the prince. Among most influential of Bosnian nobleman with the title knez was Pavle Radinovi? of Radinovi?-Pavlovi? noble family.