The siege of Wiener Neustad, part of the Austrian-Hungarian War, was an assault from January 1486 to August 1487 on the Austrian town of Wiener Neustadt. Launched by Matthias Corvinus, King of Hungary, the 18-month siege ended with the town's surrender and allowed Hungary to take control the of the surrounding Styria and the Lower Austria regions. It was the last of a series of sieges, and followed Hungary's victory in the 1485 Siege of Vienna. The broader war ended less than a year later with an armistice in 1488. Premise The city was alerted many times during the Austrian-Hungarian War. First in 1477 Grand master Johann Siebenhirter of the newly founded (1469) Order of Saint George of Carinthia "defenders of environment" occupied the city in order to defend the city. They were dedicated to defend the borders of Austrian lands from the Eastern menaces. Originally set against the Ottomans the order found itself in between Matthias of Hungary and the Holy Roman Emperor Frederick, the latter who imposed as the founder knight of the order. Siebenhirter placed the headquarters of the Order from Millstatt to Wiener Neustadt. In May 1478 he commanded the cottars of the mortgaged Hungarian villages Kismarton and Fraknó – of which he was the captain of, and in which he had spawned the Ordership – to drudge-work in the fortification labour of the city. After the siege of Vienna he visited Matthias to compromise the status of Neustadt. As a result, they concluded a truce regarding the territories owned by the Order and exchanged their prisoners of war. The treaty meant the immunization of the Order off the Austrian-Hungarian War. This was a contradicting situation as Siebenhirter kept his captain office of Neustadt in the meantime. Siebenhirter also committed himself that his knights at Wartenstein would refuse any support request from the Emperor. Also he could continue to run the Order in the lands under Matthias' authority. The siege Wiener Neustadt was a well-defended and equipped fortress town of its time. The town was surrounded by three ditches and a powerful rectangular chain of ashlar stone walls, the suburbs were protected by a wide water ditch against sudden attacks, with four gate exits on drawbridges to the city. At the Ungarthore () stood the ducal castle with high walls and four stone towers. At the back of the castle laid the Thiergarten enclosed by a