Apart from a visit by the French Parmentier brothers in 1529, for much of the 16th century the only Europeans to visit the islands were Portuguese. British and Dutch ships began arriving around the start of the 17th century and the island of Ndzwani soon became a major supply point on the route to the East Indies. Ndzwani was generally ruled by a single sultan, who occasionally attempted to extend his authority to Mayotte and Mwali; Ngazidja was more fragmented, on occasion being divided into as many as 12 small kingdoms.