Symi has long traditions of both sponge diving and shipbuilding and is mentioned in the 'Iliad' as sending three ships to assist Agamemnon’s siege of Troy. In ancient legend, Glaucus, one of the island's sons, was the master builder of Argo, the ship that would take Jason and his compadres to distant Colchis in search of the Golden Fleece. During Ottoman times it was granted the right to fish for sponges in Turkish waters. In return, Symi supplied the sultan with first-class boat builders. This exchange enriched the island – gracious mansions were built and culture and education flourished. By the early 20th century, the population was 22,500 and Symi was launching around 500 ships a year. But the Italian occupation, the advent of the steamship and the decline of the sponge industry put an end to prosperity, obliging Symi to reinvent itself as a tourist destination.