linguistic:translation
War for Austria (1479–1487)

Emperor Frederick only paid off half of the indemnity due to Matthias according to their treaty of 1477. Matthias concluded a treaty with the Swiss Confederacy on 26 March 1479, hindering the recruitment of Swiss mercenaries by the Emperor. He also entered into an alliance with Archbishop of Salzburg Bernhard II of Rohr, who allowed him to take possession of the fortresses of the Archbishopric in Carinthia, Carniola and Styria.

An Ottoman army supported by Basarab Țepeluș of Wallachia invaded Transylvania and set fire to Szászváros (now Orăștie in Romania) in late 1479. Stephen Báthory and Paul Kinizsi annihilated the marauders in the Battle of Breadfield on 13 October. Matthias united the command of all forts along the Danube to the west of Belgrade in the hand of Paul Kinizsi to improve the defence of the southern frontier. Matthias sent reinforcements to Stephen the Great, who invaded pro-Ottoman Wallachia in early 1480; Matthias launched a campaign as far as Sarajevo in Bosnia in November. He set up five defensive provinces, or banates, centred around the forts of Szörényvár (now Drobeta-Turnu Severin in Romania), Belgrade, Šabac, Srebrenik and Jajce. The next year, Matthias initiated a criminal case against the Frankapans, the Zrinskis and other leading Croatian and Slavonian magnates for their alleged participation in the 1471 conspiracy. Most barons were pardoned as soon as they consented to the introduction of a new land tax. In 1481, for a loan of 100,000 florins, Matthias seized the town of Mautern in Styria and Sankt Pölten in Lower Austria from Friedrich Mauerkircher, one of the two candidates to the Bishopric of Passau.

Sultan Mehmed II died on 3 May 1481. A civil war ensued in the Ottoman Empire between his sons Bayezid II and Cem. Defeated, Cem fled to Rhodes, where the Knights Hospitaller kept him in custody. Matthias claimed Cem's custody in the hope of using him to gain concessions from Bayezid, but Venice and Pope Innocent VIII strongly opposed this plan. In late 1481, Hungarian auxiliary troops supported Matthias's father-in-law Ferdinand I of Naples to reoccupy Otranto, which had been lost to the Ottomans the year before.

Although the "Black Army" had already laid siege to Hainburg an der Donau in January 1482, Matthias officially declared a new war on Emperor Frederick three months later. He directed the siege in person from the end of June and the town fell to him in October. In the next three months, Matthias also captured Sankt Veit an der Glan, Enzersdorf an der Fischa, and Kőszeg. The papal legate, Bartolomeo Maraschi tried to mediate a peace treaty between Matthias and the Emperor, but Matthias refused. Instead, he signed a five-year truce with Sultan Bayezid.

Matthias's marriage to Beatrice of Naples did not produce sons; he tried to strengthen the position of his illegitimate son John Corvinus. The child received Sáros Castle and inherited the extensive domains of his grandmother Elizabeth Szilágyi with his father's consent. Matthias also forced Victor of Poděbrady to renounce the Duchy of Troppau in Silesia in favour of John Corvinus in 1485. Queen Beatrice opposed Matthias's favouritism towards his son. Even so, Matthias nominated her eight-year-old nephew Ippolito d'Este Archbishop of Esztergom. The Pope refused to confirm the child's appointment for years. The "Black Army" encircled Vienna in January 1485. The siege lasted for five months and ended with the triumphal entry of Matthias, at the head of 8,000 veterans, into Vienna on 1 June. The King soon moved the royal court to the newly conquered town. He summoned the Estates of Lower Austria to Vienna and forced them to swear loyalty to him.

Matthias, by the grace of God, king of Hungary, Bohemia, Dalmatia, Croatia, Rama, Serbia, Galicia, Lodomeria, Cumania, and Bulgaria, Duke of Silesia and Luxemburg and Margrave of Moravia and Lusatia, for the everlasting memory of the matter. It is fitting that kings and princes who by heavenly decree are placed at the summit of the highest office, be adorned not only by arms but also by laws and that the people subjected to them, as well as the reins of authority, are restrained by the strength of good and stable institutions rather than by the harshness of absolute power and reprehensible abuse.

Preamble to the Decretum Maius

Upon the monarch's initiative, the Diet of 1485 passed the so-called Decretum maius, a systematic law-code which replaced many previous contradictory decrees. The law-code introduced substantial reforms in the administration of justice; the Palatine's eyre and the extraordinary county assemblies were abolished, which strengthened the position of the county courts. Matthias also decreed that in cases of the monarch's absence or minority, the Palatine was authorized to rule as Regent.

Emperor Frederick persuaded six of the seven Prince-electors of the Holy Roman Empire to proclaim his son Maximilian King of the Romans on 16 February 1486. The Emperor, however, had failed to invite the King of Bohemia — either Matthias or Vladislaus Jagiellon — to the assembly. In an attempt to prevail on Vladislaus to protest, Matthias invited him to a personal meeting. Although they formed an alliance in Jihlava in September, the Estates of Bohemia refused to confirm it and Vladislaus recognized Maximilian's election.

In the meantime Matthias continued his war against the Emperor. The "Black Army" seized several towns in Lower Austria, including Laa an der Thaya, and Stein in 1485 and 1486. He set up his chancery for Lower Austria in 1486 but he never introduced a separate seal for this realm. Matthias assumed the title of Duke of Austria at the Diet of the Lower Austrian Estates in Ebenfurth in 1487. He appointed Stephen Zápolya captain-general, Urban Nagylucsei administrator of the Archdiocese of Vienna, and entrusted the defence of the occupied towns and forts to Hungarian and Bohemian captains, but otherwise continued to employ Emperor Frederick's officials who accepted his rule. Wiener Neustadt, the last town resisting Matthias in Lower Austria, fell to him on 17 August 1487. He started negotiations with Duke Albert III of Saxony, who arrived at the head of the imperial army to fight for Emperor Frederick III. They signed a six-month armistice in Sankt Pölten on 16 December, which ended the war. Matthias offered Emperor Frederick and his son prince Maximilian, the return of Austrian provinces and Vienna, if they would renounce the treaty of 1463 and accept Matthias as Frederic's designated heir and probable the inheritor of the title of Holy Roman Emperor. Before this was settled though, Matthias died in Vienna in 1490.

King Matthias was happy to be described as "the second Attila". The Chronica Hungarorum by Johannes Thuróczy published in 1488, set the goal of glorifying Attila, which was undeservedly neglected, moreover, he introduced the famous "Scourge of God" characterization to the later Hungarian writers, because the earlier chronicles remained hidden for a long time. Thuróczy worked hard to endear Attila, the Hun king with an effort far surpassing his predecessor chroniclers. He made Attila a model for his victorious ruler, King Matthias who had Attila's abilities, with this he almost brought "the hammer of the world" to life.