Once the Premyslide bid for the Hungarian throne had failed and the attempt of Otto of Wittelsback had been frustrated by the voyvode of Transylvania, the road was free for young Charles Robert of Anjou. Cardinal Gentile, the papal legate sent to support him, graduallu won over the prelates and some powerful barons for his candidate. In 1308 a Diet was called, and Charles I acclaimed king. Yet, his claim to rule lacked two important elements. He had not yet been crowned with the venerated 'Holy Crown', still in the possession of the voyvode where Otto had been forced to leave it. Furthermore, at least half of his country was still held by opposing great landowners beyond his reach. Probably because of the change of dynasty, the crown and the other insignia, believed to have belonged to Saint Stephen, acquired a quasi-magical value for the Hungarians. Thus it was most important for the new ruler to regain the jewel; finally, on Saint Stephen's Day, 20 August 1310, Charles could be crowned in the traditional form in the royal basilica of Szekesfehervar.
To reconquer the territories usurped by the barons took much longer. Playing off one against the other and building up and armed force with the support of lesser nobles and townsmen who had been harassed by the oligarchs, Charles gradually expanded royal control over the country. In the decisive battle of Rogzony in 1319 his army, aided by the militia of the Saxon (German) settlers of the northern frontier, defeated the powerful Aba clan. This victory turned the balance in favour of the king, and when Mate Csak, the lord of the north-eastern part of Hungary, died in 1321, Charles could demonstrate royal power by moving his residence from the border-castle Temesvar to the centre of the country, his new fortress in Visegrad. With the fall of every oligarch dozens of castles with their extensive estates came into the king's hands -- more than thirty by Csak's death alone. Many of these possessions were entrusted as honores to the king's faithful men. The administration of several counties with all the royal lands within them was assigned to reliable magnates 'at the king's pleasure.' While resembling Western feudal tenures, these honours did not become hereditary or bases of particularism, at least not as long as a strong monarch wore the crown. But, of course, they contained the core of possible territorial particularism and oligarchic power under a weak king.
Charles's most significant innovations were in the field of monetary incomes for the monarchy. He reaffirmed the royal monopoly of gold and silver mining, but shared its profit with mining entrepeneurs and the lords who owned land with precious metal ore. Mining and refining increased, and the treaury's revenues permitted the currency to be placed on a new footing. In 1325 Charles ordered the minting of Hungarian gold coins, based on Florentine models, which came to be much sought after all over Europe. With the new monetary system Hungarian trade also increased so that royal income from taxes, tolls, and customs made the regalia a more substantial source of revenue than traditional dues from the domain.
Changes in the military system began before the coming of the Angevins, but it was under Charles that the country's defence was essentially transferred from the levy of castle-militias to the 'private' armies of great landowners, including the king and the queen, under the king's command. These baronial contingents were modelled on the troops of the oligarchs that had fought against each other and the king in the previous decade. They consisted mainly of lesser noblemen who took service with the rich magnates and prelates as their retainers (familiares, servientes). The retainers enjoyed full noble rights and were bound by temporary contact to thier domini whom they served in peace and war as administrators, castellans, and warriors. Later, they were also to supply the political clientele for baronial leagues. Charles also introduced French chivalric forms into his court and army, granted the first coats of arms and permitted the greater landowners to fly their own banners when joining the king on campaigns (hence the system was called 'banderial'). The new army's loyalty, just as that of the holders of honours, depended upon the personal allegiance of its baronial lords.
Military actions were augmented by diplomatic alliances with northern neighbours. Wladyslaw the Short had been an old friend, for he had spent years of exile in Hungary and in 1320 gave his sister in marriage to Charles. John of Bohemia found Hungary useful against the Habsburgs even if he was thus forced to give up his farthest-reaching designs on Poland. Charles's diplomatic successes were crowned by the meeting of the kings of Hungary, Bohemia, and Poland in 1335 in Visegrad. It was here that the Bohemian-Polish conflict was settled, the king's son, Prince Lewis's right to inherit the throne of Wladislaw the Short was confirmed, matters between Poland and the Teutonic Order were submitted to arbitration and an agreement was reached to circumvent the Vienna staple by a route over Moravia to Nuremburg. The festivities in the newly built Norman-style castle signified to participants and spectators alike that the Luxembourg-Anjou-Piast triad had brought to the regiona new stability and European political significance.