 But only these two groups, Maranao and Iranun, still speak the mutually intelligible Danao languages.The name "Maguindanao" itself was corrupted by Spanish sources into "Mindanao", which became the name for the entire island of Mindanao.In the early 15th century, Sharif Muhammad Kabungsuan, an Arab-Malay preacher from the Royal House of Malacca, arrived in what is now Malabang, introduced Islamic faith and customs, settled down with a local princess, and founded a Sultanate whose capital was Cotabato.