text: Sigismund's son-in-law, Albert of Habsburg (), was elected king in early 1438, but only after he promised always to make important decisions with the consent of the royal council. After he died in 1439, a civil war broke out between the partisans of his son, Ladislaus the Posthumous (), and the supporters of the child king's rival, Vladislaus III of Poland (). Ladislaus the Posthumous was crowned without election with the Holy Crown of Hungary, but the Diet proclaimed the coronation invalid, stating that "the crowning of kings is always dependent on the will of the kingdom's inhabitants, in whose consent both the effectiveness and the force of the crown reside". Vladislaus died fighting the Ottomans during the Crusade of Varna in 1444 and the Diet elected seven captains in chief to administer the kingdom. The talented military commander, John Hunyadi (d. 1456), was elected the sole regent in 1446.
  The Diet developed from a consultative body into an important institution of law making in the 1440s. The magnates were always invited to attend it in person. Lesser noblemen were also entitled to attend the Diet, but in most cases they were represented by delegates, who were almost always the magnates' .
  Birth of titled nobility and the Tripartitum
  Hunyadi was the first noble to receive a hereditary title from a Hungarian king, when Ladislaus the Posthumous granted him the Saxon district of Bistritz (now Bistrița in Romania) with the title perpetual count in 1453. Hunyadi's son, Matthias Corvinus (), who was elected king in 1458, rewarded further noblemen with the same title. Fügedi states that 16 December 1487 was the "birthday of the estate of magnates in Hungary", because an armistice signed on this day listed 23 Hungarian "natural barons", contrasting them with the high officers of state, who were mentioned as "barons of office". Corvinus' successor, Vladislaus II (), and Vladislaus' son, Louis II (), formally began to reward important persons of their government with the hereditary title of baron.