Sicily's economy in the fourteenth century was turbulent, and marked a drastic departure from its success in the twelfth and thirteenth centuries. Fiscal revenue in Sicily was concernedly low during Elizabeth's reign, primarily relating to Europe's declining population. Domestically, the low population meant lower revenue from domestic taxation. The lower population abroad and in mainland Italy meant that there was a lower demand for Sicilian exports, namely grain. In addition, feudal revenues began to decline significantly in approximately 1330; total feudal revenue dropped from 20691 "onze" in 1336, to 14405 "onze" in 1343. It is probable that the aristocracy pressured Elizabeth and the monarchy to reduce feudal military duties, a pressure which increased after the death of Frederick III in 1337. This pressure likely had numerous contributing factors; Elizabeth's reign was also characterized by famine, with particularly low-yielding harvests in 1345 and 1346. Increased military expenditure combined with the negative economic effects of the famine which provoked widespread debt among the aristocracy. The unstable equilibrium between the nobility and the throne characterized both Elizabeth's and her husband's reign, and resulted in a significant reduction in monarchical power. Economic historian Stephan Epstein refers to mid to late fourteenth century Sicily as a period of aristocratic hegemony.