Based on the Treaty of Tordesillas, the Spanish Crown claimed it had territorial rights in the area visited by John Cabot in 1497 and 1498 CE. However, Portuguese explorers like João Fernandes Lavrador would continue to visit the north Atlantic coast, which accounts for the appearance of "Labrador" on maps of the period. In 1501 and 1502 the Corte-Real brothers explored Newfoundland (Terra Nova) and Labrador claiming these lands as part of the Portuguese Empire. In 1506, King Manuel I of Portugal created taxes for the cod fisheries in Newfoundland waters. João Álvares Fagundes and Pêro de Barcelos established fishing outposts in Newfoundland and Nova Scotia around 1521 CE; however, these were later abandoned, with the Portuguese colonizers focusing their efforts on South America. The extent and nature of Portuguese activity on the Canadian mainland during the 16th century remains unclear and controversial.