In 1418 Dalmatia again passed into the hands of Venice. Then it was that Ragusa revolted, and, three years later, she established successfully an independence, which she enjoyed for almost four hundred years. A steady commercial progress marked this period of her history, and it only reached its climax after the fall of Venice in 1797. As early as 1417 slave-dealing was forbidden in Ragusa and adjudged by the assembly as “base, wicked and abominable.” A foundling hospital was established in 1432, and in 1435 teachers were invited from Italy to instruct in the public schools. The little principality became the haven of many wealthy and noble families from the Slavonic kingdoms in the interior, who had been driven from their lands by the marauding Turks. But Ragusa, on the other hand, made friends with the deceitful Mohammedans, traded with them, and, at the same time, cannily strengthened her fortifications against them. Ragusa made treaties of commerce with Spain in 1494, with France in 1508 and with Egypt in 1510, which latter treaty smoothed the sea for her along the course to the East Indies. Her “argosies” (the word “argosy” means literally “a vessel of Ragusa”) were to be found in every commercial port, and, at the time of the fall of Venice, her mercantile marine had risen rapidly to more than four hundred sail. But during this period of trade-building the misfortunes of Ragusa were many. Only by the loyalty and indomitable pluck of her sons was she able to rise so many times from her dust and ashes, while the whole world marvelled at such determination to outlive the destruction wrought by nature and the elements. In 1462 plague broke out among the inhabitants of the town and two thousand people succumbed to its ravages. The same year a disastrous fire destroyed the Rector’s palace and the arsenal. May 17, 1520, was the date on which commenced a series of earthquake shocks, which continued intermittently for twenty months. Many houses were demolished and it became the custom of the people to place the passover mark, I. H. S., above their doors as a devout entreaty for Divine protection. Finally, the earthquakes ceased, but six years later the germs of the plague were carried to Ragusa in the stuffs of a trader from Ancona. The unfortunate merchant was dragged through the streets and tortured by the infuriated, panic-stricken citizens, the Senate fled to Gravosa, and only a small guard remained to quiet and to ease the sufferings of the terrified inhabitants. For six long months the pestilence raged within the walls and no less than twenty thousand souls fell victims to its terrible havoc. Then Turkey in the east, and Venice in the west, took advantage of Ragusa’s weakness and preyed upon her, the Turks especially making the most of her misfortunes for their own aggrandizement. The plague re-appeared from time to time, and in 1580 and 1639 the town was again visited by earthquakes.