Villani affirms that the title of prior was derived from a verse of the Gospel, where Christ says to His disciples, "Vos estis priores." What is certain is that by means of this reform the guilds, or rather commerce and trade, had the whole government of the Republic in their hands; and it should also be noted that although the above-mentioned guilds, together with that of the jurists and notaries, constituted the seven greater arts, yet the legal guild--perhaps because it represented neither industry nor commerce--is left unnoticed by the chroniclers at this point. Henceforward the Commonwealth is a true republic of traders, and only to be governed by members of the guilds. Every title of nobility, whether old or new, becomes an impediment rather than a privilege. Consequently many of the principal families began to change their names in order to disguise their former rank. The Tornaquinci divided into Popoleschi, Tornabuoni, Giachinotti, &c.; the Cavalcanti became Malatesti and Ciampoli; and others assumed fresh names.[319] Nevertheless, many proudly clung to their ancient appellations and titles; and when King Charles' son, the Prince of Salerno, was summoned to Naples from Provence, he halted in Florence by the way on purpose to imitate his father by creating new knights. By these artificial devices it was hoped to give new strength to an aristocracy that was doomed to decline by the natural course of events; but the means employed were too utterly opposed to the political and social temper of Florence to have the slightest success there. No longer fettered by Pope and emperor, and emancipated from the oppressive patronage of King Charles, who was now absorbed in Sicilian matters, the Florentines had organised the constitution in the manner that suited them best, and by entrusting the greater guilds with the management of the State gained a real predominance in Tuscany that they turned most skilfully to account for the extension of their trade. The politico-commercial league, concluded in March, 1282, to which we have already alluded, proved most beneficial to their interests, and the subjection of neighbouring towns and territories was another means to the same end. Nevertheless, the two Ghibelline cities of Arezzo and Pisa still remained hostile to Florence. The former was a threatening presence in the upper Val d'Arno, while the latter, with its wealth, power, and command of the sea, was a danger to the lower valley, and, standing on the road to Leghorn and Porto Pisano, was an obstruction to the maritime trade of Florence. Hence it was obvious that sooner or later the Republic would be forced to combine with friendly neighbours and new allies against both these foes, and especially against Pisa. Free access to the sea-board was more indispensable than ever to the Florentine trade, and should Pisa continue to block the way, the Republic would reap nothing from the successes it had already achieved.