By the 17th century, when the 'Malawi' state had been unified, the Portuguese had made some contact with the Chewa. Although the Portuguese did not reach the heartland of the chiefdom, there are well documented records of contacts between 1608 and 1667. By 1750, several 'Malawi' dynasties had consolidated their positions in different parts of central Malawi, however the Chewa had managed to distinguish themselves from their neighbours through language, by having special tattoo marks (mphini), and by the possession of a religious system based on the nyau secret societies.