The propagation of universities was not necessarily a steady progression, as the 17th century was rife with events that adversely affected university expansion. Many wars, and especially the Thirty Years' War, disrupted the university landscape throughout Europe at different times. War, plague, famine, regicide, and changes in religious power and structure often adversely affected the societies that provided support for universities. Internal strife within the universities themselves, such as student brawling and absentee professors, acted to destabilize these institutions as well. Universities were also reluctant to give up older curricula, and the continued reliance on the works of Aristotle defied contemporary advancements in science and the arts. This era was also affected by the rise of the nation-state. As universities increasingly came under state control, or formed under the auspices of the state, the faculty governance model (begun by the University of Paris) became more and more prominent. Although the older student-controlled universities still existed, they slowly started to move toward this structural organization. Control of universities still tended to be independent, although university leadership was increasingly appointed by the state.