Not less prosperous than the silk manufactures were the corders and beaters of wool, also united into associations. They gave a great impulse to traffic and navigation. The beginnings of our civilization were born of industrial arts. The marines artisans, and tradesmen formed the only army of the Republic when it made war on feudatories and compelled them to swear allegiance to the commune. These brave plebeians--to-day operatives, to-morrow soldiers, not more masters of the shuttle and the oar than of the sword, tempestuous in character but fervent in faith--created in Genoa fruitful industries and immense social power; and though in the fury of faction they sometimes shed blood in the streets of Genoa, they atoned it by giving her, through formidable fleets, the dominion of the seas. Guglielmo Embriaco, the hero of the first crusade, is the representative of this Genoese thrift and courage. Our armies were nothing more than associations. Such companies subdued the Euxine. The Giustiniani captured Scio, Samos, and other islands, and divided their gains _pro rata_ per man in proportion to the expense which each had borne; the Cattaneo at Phocis, the Gattilusio at Mytilene, and the Zaccaria in Negroponte. Elis and Achaia adopted the same rule. It rarely happened that one who was not inscribed in a trade and to the commune obtained any position as a master-workman. The very nobleman who was a Ghibeline outside the walls became a Guelph when he established his residence in the city; and though from his castles in the passes of the Apennines he might have once plotted to invade us, he had no sooner recorded himself as a citizen than he counted it an honour to guide our fleets and overthrow our enemies. There was at one time a law which forbade the nobles to command even a ship; and many great nobles enrolled themselves with the people to open the path to naval and military authority. The mark of these Guelph institutions on the people of Genoa was deep and enduring. The Genoese of our day are living proof of their lasting influence. Labour and banking produced immense wealth. The Genoese became the bankers of Europe. In the year 1200 they drew the first bill of exchange.[40] It was drawn on Palermo. They diffused the Arabic system of notation. In 1148 they created, for the conquest of Tortosa, the first public debts which they afterwards consolidated, appropriating the city and port customs to pay the interest. They founded the Bank of St. George, on whose model those of England and Holland were constructed, and they planted colonies everywhere. Along the inhospitable coasts of the Caspian and Aral, in Turchestan and Thibet, the pilgrim was safe in person and property who declared, “I am a Genoese.”