With equal sagacity they pursued the same course in the years during which they were menaced by the powerful Dukes of Milan who sought to become masters of all Italy, and also when threatened from the south by the enmity of King Ladislaus of Naples. The art of stirring division among their foes, of supporting the weaker party against overbearing neighbours, of constantly contriving to rouse half Italy against every potentate risen to sufficient strength to be a terror to their own Republic, was the invariable means by which Florence maintained her independence in the midst of States who were losing their liberty, and in the midst of the numerous and formidable foes pressing about her on all sides. And this successful policy was the work of the greater guilds, or rather of the prosperous trading class (_popolani grassi_). These mercantile aristocrats ruled the Republic with so much energy and zeal, precisely because the aggrandisement of Florence conduced at the same time to the increase of their own wealth and commerce. Thus a city whose population was seldom more than 100,000, and often shrank far below that number, and whose narrow territory was surrounded by so many enemies, was enabled to become a State feared by the rest of Italy, and respected throughout Europe. These Florentine merchants were so jealous of their liberty as to deem no sacrifice too vast for its preservation, and were neither bewildered nor daunted by any danger, even when their trade was at stake. In fact, although so obstinately Guelph, and connected with Rome by so many commercial interests and ties, we find them ready to combat the Pope himself, when he made attacks on their liberty, and see them giving the name of the _Eight Saints_ to the magistrates charged to conduct the campaign against Gregory XI. (1376). In the like manner we find them carrying on a war with the Visconti of Milan at a yearly cost of millions of florins, without the resources of the Republic being exhausted, or the courage of its rulers worn out. VI. Nevertheless, it would be an error to suppose that the domination of the greater guilds was assured and uncontested in the interior, at least, of the city. On the day when the scheme was first mooted, in the Calimala court, of placing these guilds at the head of the government, they speedily recognised that the possibility of success was solely owed to the fact of their having fought and conquered the nobles with the help of the lesser arts. Hence, on the one hand, they had to face their natural and inveterate foes, the survivors of the feudal order, and on the other the lesser guilds coveting a share in the government which they had helped to establish. Thus the Republic comprised three classes of citizens and three separate parties. It is true that the greater guilds constituted by far the stronger of the three factions, but the others might become, if united, a very formidable opposition. And their union was no impossible contingency.