Excerpts from Books and Wikipedia
"In the other major kingdom that comprised the Monarchy–Hungary–it was quite a different story. There the opportunity for a similar axis appeared to be even greater, for the concentration of land, wealth and power in the hands of a few magnates was even more pronounced, the greater part of the wealth of the country being owned by just fifty landowning families. But the situation was a great deal more complicated. Although the Habsburgs had nominally ruled the entire kingdom of Hungary since the last Jagiellon king fell fighting the Turks at the battle of Mohács in 1526, they had been able to make good their claim only to about a third, a crescent of territory stretching from south-west to north-east. Of the rest, another third, comprising the centre, was ruled directly by the Turks, while the eastern third formed the Principality of Transylvania, ruled by a Turkish vassal. Following the great reconquista of the 1680s and 1690s, the Peace of Karlowitz of 1699 placed the entire kingdom, including Transylvania, under Habsburg rule de facto as well as de jure. . . . As we have seen, Hungary was unusually diverse. At the core, however, both geographically and metaphorically, stood the Magyar gentry, the rock against which every Habsburg attempt at integration foundered." [Blanning: Pursuit of Glory, p. 222-3]