The economic wealth of the Republic was partially the result of the land it developed, but especially of seafaring trade. With the help of skilled diplomacy, Dubrovnik merchants travelled lands freely and the city had a huge fleet of merchant ships () that travelled all over the world. From these travels they founded some settlements, from India to America, and brought parts of their culture and flora home with them. One of its keys to success was not conquering, but trading and sailing under a white flag with the word (freedom) prominently featured on it. The flag was adopted when slave trading was abolished in 1418. Conversos, Jews from Spain and Portugal, were attracted to the city. In May 1544, a ship landed there filled exclusively with Portuguese refugees, as Balthasar de Faria reported to King John. During this time there worked in the city one of the most famous cannon and bell founders of his time: Ivan Rabljanin (Magister Johannes Baptista Arbensis de la Tolle). Already in 1571 Dubrovnik sold its protectorate over some Christian settlements in other parts of the Ottoman Empire to France and Venice. At that time there was also a colony of Dubrovnik in Fes in Morocco. The bishop of Dubrovnik was a Cardinal protector in 1571. At that time there were only 16 other countries which had Cardinal protectors; those being France, Spain, Austria, Portugal, Poland, England, Scotland, Ireland, Naples, Sicily, Sardinia, Savoy, Lucca, Greece, Illyria, Armenia and Lebanon.