by August of that year. In France, the king's personal expenditure on dowries, gratuities, the upkeep of the palace, his travels and his wardrobe, consumed the entirety of the royal income. Therefore, a monopoly on salt, an essential commodity, was established in 1341; monopolies in salt had already been established in Kingdom of Castile and Venice in the 1330s. The French salt tax or gabelle itself never amounted to more than 2%. Fouages were also levied in 1342 and 1349. The Italian city states were booming at the start of the decade. In 1340, Francesco Balducci Pegolotti wrote his Practica della mercatura. Meanwhile, rulers such as the Neapolitan princes had begun withdrawing massive funds from Florentine banks. England found itself unable to repay its debts, and both factors resulted in a crisis of confidence in the Florentine banks The family-based banks and mercantile associations of Florence and Genoa generally kept only 25–30% of their capital in liquid assets, and between 1341 and 1346, many of the most important of the Florentine banks collapsed. — an "avalanche of bankruptcies", in the words of Robert Fossier. These were owned by the following banking families: the Acciaiuolis, the Bonaccorsis, the Cocchis, the Antellesis, the Corsinis, the Uzzanos, the Perendolis, the Peruzzis and the Bardis. Social unrest The situation in the towns remained delicate: while on one hand the trades were dominant, and Villani counted no fewer than 200 textile workshops in Florence around 1340, working conditions and entry restrictions imposed by the guilds created tensions with the unemployed and unskilled labourers. Strikes or grèves occurred in Ghent in 1337–1345 and in Florence in 1346. In 1349–1350, the fullers and weavers of Ghent and Liège massacred each other. The failures in the food supply in the regions of Provence and Lyon, in 1340 and 1348 respectively, affected contemporaries particularly harshly. This was not just because these generations were unused to them, but because they were accompanied by war and followed by epidemic in this decade. The Black Plague In 1340, the total population of Europe was 54 million; by 1450, it would be 37 million, a 31% drop in only a century. In addition to the earlier social and economic decline, the Black Plague is identified as the superficial cause, which struck Europe and wiped out a full third of the population in short space of 1348–1350. It has been described as "a pandemic