The Hungarian nobility consisted of a privileged group of people, most of whom owned landed property, in the Kingdom of Hungary. Initially, a diverse category of people were mentioned as noblemen, but from the late 12th century only the high-ranking royal officials were regarded nobles. Most aristocrats claimed a late-9th-century Magyar leader for their ancestor; others were descended from foreign knights; and local Slavic chiefs were also integrated in the nobility. Less illustrious individuals, known as castle warriors, also held landed property and served in the royal army. Most privileged laymen called themselves royal servants to emphasize their direct contact to the monarchs from the 1170s. The Golden Bull of 1222 enacted their liberties, especially their tax-exemption and the limitation of their military obligations. From the 1220s, the royal servants were associated with the nobility and the highest-ranking officials were known as barons of the realm. Only those who owned allods – lands free of obligations – were regarded true noblemen, but other privileged groups of landowners, known as conditional nobles, also existed.
Simon of Kéza was the first to claim, in the 1280s, that the noblemen held real authority in the kingdom. The counties developed into institutions of noble autonomy and the nobles' delegates attended the Diets (or parliaments). The wealthiest barons built stone castles which enabled them to control vast territories, but royal authority was restored in the early 14th century. Louis I of Hungary introduced an entail system and enacted the principle of "one and the selfsame liberty" of all noblemen. Actually, legal distinctions between true noblemen and conditional nobles prevailed, and the most powerful nobles employed lesser noblemen as their familiares (or retainers). According to customary law, only males inherited noble estates, but the kings could "promote a daughter to a son", authorizing her to inherit her father's lands. Noblewomen who had married a commoner could also claim their inheritance – the daughters' quarter – in land.
The monarchs granted hereditary titles and the poorest nobles lost their tax-exemption from the middle of the 15th century, but the Tripartitum – a frequently cited compilation of customary law – maintained the notion of all noblemen's equality. Medieval Hungary was divided into three parts – Royal Hungary, Transylvania and Ottoman Hungary – due to the expansion of the Ottoman Empire in the 1570s. The princes of Transylvania supported the noblemen's fight against the Habsburg kings in Royal Hungary, but they prevented the Transylvanian noblemen from challenging their authority. Ennoblement of whole groups of people was not unusual in the 17th century. After the Diet was divided into two chambers in Royal Hungary in 1608, noblemen with a hereditary title had a seat in the Upper House, other nobles sent delegates to the Lower House.
Most parts of medieval Hungary were integrated in the Habsburg Monarchy in the 1690s. The monarchs confirmed the nobles' privileges several times, but their attempts to strengthen royal authority regularly brought them into conflicts with the nobility, who made up about 4,6% of the society. Reformist noblemen demanded the abolition of noble privileges from the 1790s, but their program was enacted only during the Hungarian Revolution of 1848. Most noblemen lost their estates after the emancipation of their serfs, but the aristocrats preserved their distinguished social status. State administration employed thousands of impoverished noblemen in Austria-Hungary. Prominent (mainly Jewish) bankers and industrialists were awarded with nobility, but their social status remained inferior to traditional aristocrats. Noble titles were abolished only in 1947, months after Hungary was proclaimed a republic.
The Magyars (or Hungarians) dwelled in the Pontic steppes when they first appeared in the written sources in the mid-9th century. Muslim merchants described them as wealthy nomadic warriors, but they also noticed that the Magyars had extensive arable lands. Masses of Magyars crossed the Carpathian Mountains after the Pechenegs invaded their lands in 894 or 895. They settled in the lowlands along the Middle Danube, annihilated Moravia and defeated the Bavarians in the 900s. Slovak historians write, at least three Hungarian noble kindreds[note 1] were descended from Moravian aristocrats. Historians who say that the Vlachs (or Romanians) were already present in the Carpathian Basin in the late 9th century propose that the Vlach knezes (or chieftains) also survived the Hungarian Conquest. Neither of the two continuity theories is universally accepted.
Constantine Porphyrogenitus recorded around 950 that the Hungarians were organized into tribes and each had its own "prince". The tribal leaders most probably bore the title úr, as it is suggested by Hungarian terms – ország (now "realm") and uralkodni ("to rule") – deriving from this noun. Porphyrogenitus noted that the Magyars spoke both Hungarian and "the tongue of the Chazars", showing that at least their leaders were bilingual.
Archaeological research revealed that most settlements comprised small pit-houses and log cabins in the 10th century, but literary sources mentioned that tents were still in use in the 12th century. No archeological finds evidence fortresses in the Carpathian Basin in the 10th century, but fortresses were also rare in Western Europe during the same period. A larger log cabin – measuring 5 m × 5 m (16 ft × 16 ft) – which was built on a foundation of stones in Borsod was tentatively identified as the local leader's abode.
More than a 1,000 graves yielding sabres, arrow-heads and bones of horses show that mounted warriors formed a significant group in the 10th century. The highest-ranking Hungarians were buried either in large cemeteries (where hundreds of graves of men buried without weapons surrounded their burial places), or in small cemeteries with 25–30 graves. The wealthy warriors' burial sites yielded richly decorated horse harness, and sabretaches ornamented with precious metal plaques. Rich women's graves contained their braid ornaments and rings made of silver or gold and decorated with precious stones. The most widespread decorative motifs which can be regarded as tribal totems – the griffin, wolf and hind – were rarely applied in Hungarian heraldry in the following centuries. Defeats during the Hungarian invasions of Europe and clashes with the paramount rulers from the Árpád dynasty decimated the leading families by the end of the 10th century. The Gesta Hungarorum, which was written around 1200, claimed that dozens of noble kindreds flourishing in the late 12th century[note 2] had been descended from tribal leaders, but most modern scholars do not regard this list as a reliable source.