The Malagasy are the biggest ethnic group in Madagascar. They are identified with seafaring Austronesian peoples who settled on the island over 1,500 years ago.
Malagasy, which is also the language of the people, is an official Madagascan language. This seems well within reason seeing that the language has been spoken on the island before the 5th century.
The language is also the most spoken Astronesian language in the world.