madeira's official written history began in 1418, when two captains under service to prince henry the navigator, joão gonçalves zarco and tristão vaz teixeira, were pushed by a storm to an island which they named porto santo (english: "holy harbour"). the following year, an organised expedition was sent to this new land to take possession of the island on behalf of the portuguese crown. later, the new settlers saw an island to the southwest, and so the larger island of madeira was discovered.