The first reference to the island of São Jorge was made in 1439, but the actual date of discovery is unknown. In 1443, the island was already inhabited, but active settlement only began with the arrival of the noble Flemish native Willem van der Haegen. Arriving at Topo, where he lived and died, he became known as "Guilherme da Silveira" to the islanders. João Vaz Corte-Real received the captaincy of the island in 1483. Velas became a town before the end of the 15th century. By 1490, there were 2,000 Flemings living in the islands of Terceira, Pico, Faial, São Jorge and Flores. Because there was such a large Flemish settlement, the Azores became known as the Flemish Islands or the Isles of Flanders. Prince Henry the Navigator was responsible for this settlement. His sister, Isabel, was married to Duke Philip of Burgundy, of which Flanders was a part. There was a revolt against Philip's rule, and disease and hunger became rampant. Isabel appealed to Henry to allow some of the unruly Flemings to settle in the Azores. He granted this and supplied them with the necessary transportation and goods.