Basque whalers who vanished from the seas of Earth once sailed these seas. They founded a new Bilbao which thrived for a brief time before being mysteriously destroyed.
The Madagascar was a merchant ship which disappeared between Melbourne and London in 1853. She, her crew of 60 and her 110 passengers found themselves sailing in strange seas. They founded the most remote colony the British Throne has ever seen and renamed it Madagascar.
The crew of the Medici were surprised to discover that Madagascar creatures are a bit different.