The city quickly generated a highly sophisticated work force. Its artisans produced the Mediterranean world's most elegant silks, carved ivories and gold enamels. Its engineers constructed the immense walls that kept all enemies out of Constantinople until 1204. The recent excavations of the harbor of Theodosius (today Yenikapi) have yielded more than 30 boats and their cargoes and shown how the capital attracted traders and craftsmen from across the Mediterranean. Venice, Genoa and Pisa established quarters within the city, while Syrian and Russian merchants stayed in particular residences when they came to trade. In the 1090s, as the western forces of the First Crusade arrived at Constantinople, they were overcome with awe at the wealth and sophistication of the eastern capital, the like of which they had not even imagined. The city was larger than any in Western Europe, with a population of about 500,000— a level not attained by Paris until the 17th century.