Since the revival of interest in national origins during the Renaissance, prompted by the rediscovery of Tacitus's history of the pagan tribes which challenged the decaying Roman Empire, history steadily gained respectability as an academic subject at schools and universities. The questioning of philosophical and theological certainties and authorities during the Renaissance and Reformation period engendered an identity crisis, when late medieval Christian societies were confronted with the un-Christian heritage of classical antiquity. Poland-Lithuania was no exception: Italian and German Humanism had reached Cracow, the old Polish capital, even before Bona Sforza (1494–1557), the daughter of Gian Galeazzo, duke of Milan, and Isabella of Aragon, married king Sigismund I in 1518 and brought Italian artists and scholars to the Polish court. A society as steeped in the culture of classical antiquity as that of the Polish-Lithuanian nobility took seriously Cicero's dictum that ‘not to know what happened in the past, means ever to remain a child’. Its sense of the past was greatly enhanced by the accumulation of political, legal and economic privileges since the late fourteenth century, which prevented the Polish king from collecting taxes, declaring war or passing any new laws without the nobility's consent. For politically active citizens, the past provided a valuable set of examples and models for future action and political legitimacy, boosting their self-confidence.